1
|
Abstract
Radiocarbon's natural production, radiative decay, and isotopic rarity make it a unique tool to probe carbonaceous systems in the life and earth sciences. However, the difficulty of current radiocarbon (14C) detection methods limits scientific adoption. Here, two-color cavity ring-down spectroscopy detects 14CO2 in room-temperature samples with an accuracy of one-tenth the natural abundance in 3 min. The intracavity pump-probe measurement uses two cavity-enhanced lasers to cancel out cavity ring-down rate fluctuations and strong one-photon absorption interference (>10 000 1/s) from hot-band transitions of CO2 isotopologues. Selective, room-temperature detection of small 14CO2 absorption signals (<1 1/s) reduces the technical and operational burdens for cavity-enhanced measurements of radiocarbon, which can benefit a wide range of applications like biomedical research and field-detection of combusted fossil fuels.
Collapse
Affiliation(s)
- Daniel McCartt
- Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550, United States
| | - Jun Jiang
- Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550, United States
| |
Collapse
|
2
|
Trovatello C, Katsch F, Li Q, Zhu X, Knorr A, Cerullo G, Dal Conte S. Disentangling Many-Body Effects in the Coherent Optical Response of 2D Semiconductors. Nano Lett 2022; 22:5322-5329. [PMID: 35759746 PMCID: PMC9284612 DOI: 10.1021/acs.nanolett.2c01309] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
In single-layer (1L) transition metal dichalcogenides, the reduced Coulomb screening results in strongly bound excitons which dominate the linear and the nonlinear optical response. Despite the large number of studies, a clear understanding on how many-body and Coulomb correlation effects affect the excitonic resonances on a femtosecond time scale is still lacking. Here, we use ultrashort laser pulses to measure the transient optical response of 1L-WS2. In order to disentangle many-body effects, we perform exciton line-shape analysis, and we study its temporal dynamics as a function of the excitation photon energy and fluence. We find that resonant photoexcitation produces a blue shift of the A exciton, while for above-resonance photoexcitation the transient response at the optical bandgap is largely determined by a reduction of the exciton oscillator strength. Microscopic calculations based on excitonic Heisenberg equations of motion quantitatively reproduce the nonlinear absorption of the material and its dependence on excitation conditions.
Collapse
Affiliation(s)
- Chiara Trovatello
- Dipartimento
di Fisica, Politecnico di Milano, Piazza L. da Vinci 32, I-20133 Milano, Italy
| | - Florian Katsch
- Institut
für Theoretische Physik, Nichtlineare Optik und Quantenelektronik, Technische Universität Berlin, 10623 Berlin, Germany
| | - Qiuyang Li
- Department
of Chemistry, Columbia University, New York, New York 10027, United States
| | - Xiaoyang Zhu
- Department
of Chemistry, Columbia University, New York, New York 10027, United States
| | - Andreas Knorr
- Institut
für Theoretische Physik, Nichtlineare Optik und Quantenelektronik, Technische Universität Berlin, 10623 Berlin, Germany
| | - Giulio Cerullo
- Dipartimento
di Fisica, Politecnico di Milano, Piazza L. da Vinci 32, I-20133 Milano, Italy
| | - Stefano Dal Conte
- Dipartimento
di Fisica, Politecnico di Milano, Piazza L. da Vinci 32, I-20133 Milano, Italy
| |
Collapse
|
3
|
Fuentes-Domínguez R, Naznin S, La Cavera III S, Cousins R, Pérez-Cota F, Smith RJ, Clark M. Polarization-Sensitive Super-Resolution Phononic Reconstruction of Nanostructures. ACS Photonics 2022; 9:1919-1925. [PMID: 35726241 PMCID: PMC9204812 DOI: 10.1021/acsphotonics.1c01607] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Indexed: 05/28/2023]
Abstract
In this paper, we show for the first time the polarization-sensitive super-resolution phononic reconstruction of multiple nanostructures in a liquid environment by overcoming the diffraction limit of the optical system (1 μm). By using time-resolved pump-probe spectroscopy, we measure the acoustic signature of nanospheres and nanorods at different polarizations. This enables the size, position, and orientation characterization of multiple nanoparticles in a single point spread function with the precision of 5 nm, 3 nm, and 1.4°, respectively. Unlike electron microscopy where a high vacuum environment is needed for imaging, this technique performs measurements in liquids at ambient pressure, ideal to study the insights of living specimens. This is a potential path toward super-resolution phononic imaging where the acoustic signatures of multiple nanostructures could act as an alternative to fluorescent labels. In this context, phonons also offer the opportunity to extract information about the mechanical properties of the surrounding medium as well as access to subsurface features.
Collapse
Affiliation(s)
- Rafael Fuentes-Domínguez
- Optics
and Photonics Group, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - Shakila Naznin
- Optics
and Photonics Group, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - Salvatore La Cavera III
- Optics
and Photonics Group, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - Richard Cousins
- Nanoscale
and Microscale Research Centre, University
of Nottingham, University Park, Nottingham NG7 2RD, United
Kingdom
| | - Fernando Pérez-Cota
- Optics
and Photonics Group, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - Richard J. Smith
- Optics
and Photonics Group, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - Matt Clark
- Optics
and Photonics Group, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| |
Collapse
|
4
|
Belykh VV, Skorikov ML, Kulebyakina EV, Kolobkova EV, Kuznetsova MS, Glazov MM, Yakovlev DR. Submillisecond Spin Relaxation in CsPb(Cl,Br) 3 Perovskite Nanocrystals in a Glass Matrix. Nano Lett 2022; 22:4583-4588. [PMID: 35621509 DOI: 10.1021/acs.nanolett.2c01673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Lead halide perovskite nanocrystals in a glass matrix are a promising platform for optoelectronic applications due to their excellent optical properties combined with outstanding stability against the environment. We reveal the potential of this system for spintronics by studying the electron spin properties of CsPb(Cl,Br)3 nanocrystals in a fluorophosphate glass matrix. Using optical spin orientation and spin depolarization with a radio frequency field, we measure longitudinal spin relaxation time, T1, reaching several hundreds of microseconds at low temperatures. This time T1 corresponds to a spin state with a small g factor, which we attribute to a weakly exchange-coupled electron-hole pair with antiparallel spins.
Collapse
Affiliation(s)
- Vasilii V Belykh
- P.N. Lebedev Physical Institute of the Russian Academy of Sciences, 119991 Moscow, Russia
| | - Mikhail L Skorikov
- P.N. Lebedev Physical Institute of the Russian Academy of Sciences, 119991 Moscow, Russia
| | - Evgeniya V Kulebyakina
- P.N. Lebedev Physical Institute of the Russian Academy of Sciences, 119991 Moscow, Russia
| | - Elena V Kolobkova
- St. Petersburg State Institute of Technology (Technical University), 190013 St. Petersburg, Russia
- Research Center for Optical Materials Science, ITMO University, 199034 St. Petersburg, Russia
| | - Maria S Kuznetsova
- Spin Optics Laboratory, St. Petersburg State University, 198504 St. Petersburg, Russia
| | - Mikhail M Glazov
- Ioffe Institute, Russian Academy of Sciences, 194021 St. Petersburg, Russia
| | - Dmitri R Yakovlev
- P.N. Lebedev Physical Institute of the Russian Academy of Sciences, 119991 Moscow, Russia
- Ioffe Institute, Russian Academy of Sciences, 194021 St. Petersburg, Russia
- Experimentelle Physik 2, Technische Universität Dortmund, 44221 Dortmund, Germany
| |
Collapse
|
5
|
Maier A, Strauß F, Kohlschreiber P, Schedel C, Braun K, Scheele M. Sub-nanosecond Intrinsic Response Time of PbS Nanocrystal IR-Photodetectors. Nano Lett 2022; 22:2809-2816. [PMID: 35311295 DOI: 10.1021/acs.nanolett.1c04938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Colloidal nanocrystals (NCs), especially lead sulfide NCs, are promising candidates for solution-processed next-generation photodetectors with high-speed operation frequencies. However, the intrinsic response time of PbS-NC photodetectors, which is the material-specific physical limit, is still elusive, as the reported response times are typically limited by the device geometry. Here, we use the two-pulse coincidence photoresponse technique to identify the intrinsic response time of 1,2-ethanedithiol-functionalized PbS-NC photodetectors after femtosecond-pulsed 1560 nm excitation. We obtain an intrinsic response time of ∼1 ns, indicating an intrinsic bandwidth of ∼0.55 GHz as the material-specific limit. Examination of the dependence on laser power, gating, bias, temperature, channel length, and environmental conditions suggest that Auger recombination, assisted by NC-surface defects, is the dominant mechanism. Accordingly, the intrinsic response time might further be tuned by specifically controlling the ligand coverage and trap states. Thus, PbS-NC photodetectors are feasible for gigahertz optical communication in the third telecommunication window.
Collapse
Affiliation(s)
- Andre Maier
- Institute of Physical and Theoretical Chemistry, Universität Tübingen, Auf der Morgenstelle 18, D-72076Tübingen, Germany
- Center for Light-Matter Interaction, Sensors and Analytics LISA+, Universität Tübingen, Auf der Morgenstelle 15, D-72076 Tübingen, Germany
| | - Fabian Strauß
- Institute of Physical and Theoretical Chemistry, Universität Tübingen, Auf der Morgenstelle 18, D-72076Tübingen, Germany
- Center for Light-Matter Interaction, Sensors and Analytics LISA+, Universität Tübingen, Auf der Morgenstelle 15, D-72076 Tübingen, Germany
| | - Pia Kohlschreiber
- Institute of Physical and Theoretical Chemistry, Universität Tübingen, Auf der Morgenstelle 18, D-72076Tübingen, Germany
- Center for Light-Matter Interaction, Sensors and Analytics LISA+, Universität Tübingen, Auf der Morgenstelle 15, D-72076 Tübingen, Germany
| | - Christine Schedel
- Institute of Physical and Theoretical Chemistry, Universität Tübingen, Auf der Morgenstelle 18, D-72076Tübingen, Germany
| | - Kai Braun
- Institute of Physical and Theoretical Chemistry, Universität Tübingen, Auf der Morgenstelle 18, D-72076Tübingen, Germany
- Center for Light-Matter Interaction, Sensors and Analytics LISA+, Universität Tübingen, Auf der Morgenstelle 15, D-72076 Tübingen, Germany
| | - Marcus Scheele
- Institute of Physical and Theoretical Chemistry, Universität Tübingen, Auf der Morgenstelle 18, D-72076Tübingen, Germany
- Center for Light-Matter Interaction, Sensors and Analytics LISA+, Universität Tübingen, Auf der Morgenstelle 15, D-72076 Tübingen, Germany
| |
Collapse
|
6
|
Udai A, Aiello A, Aggarwal T, Saha D, Bhattacharya P. Gradual Carrier Filling Effect in "Green" InGaN/GaN Quantum Dots: Femtosecond Carrier Kinetics with Sequential Two-Photon Absorption. ACS Appl Mater Interfaces 2021; 13:45033-45039. [PMID: 34495630 DOI: 10.1021/acsami.1c11096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Quantum dots (QDs) allow for a significant amount of strain relaxation, which is helpful in GaN systems where a large lattice mismatch needs to be accommodated. InGaN QDs with a large indium composition are intensively investigated for light emitters requiring longer wavelengths. These are especially important for developing high-efficiency white light sources. Understanding the carrier dynamics in this large lattice-mismatched system is essential to improving the radiative efficiency while circumventing high defect density. This work investigates femtosecond carrier and photon dynamics in self-organized In0.27Ga0.73N/GaN QDs grown by molecular beam epitaxy using transient differential absorption spectroscopy, which measures the differential absorption coefficient (Δα) with and without an optical pump. Due to 3D quantum confinement and the small effective mass of InGaN, the low density of states in the conduction band is easily filled with electrons. In contrast, the GaN barrier region is replete with a high density of electrons due to a large effective mass. This contrast in carrier density creates a unique phenomenon in the dynamics, showing a change in the differential absorption coefficient (Δα) sign from negative to positive with time. The ultrafast microscopic processes indicate that right after the optical pump and first photon absorption, the valence (conduction) band states are depleted (replete) of electrons. This ground-state bleaching process makes Δα negative, and the probe beam is not absorbed. The electrons are then gradually transferred from the GaN barrier into InGaN QDs, which absorb the second photon from the probe beam (excited-state absorption), making Δα positive. The presence of excited-state carriers with a long lifetime is indicative of the enhanced availability of carriers for radiative recombination. This effect also promotes stimulated emission and amplified spontaneous emission, which can be used to develop lasers and superluminescent LEDs, respectively. Measurements with multiple pump powers and temperatures further confirm that the efficacy of InGaN QDs is enhanced by this effective mass contrast and 3D reservoir of carriers from the GaN barrier. This effect can be used to improve the internal quantum efficiency of GaN-based light emitters.
Collapse
Affiliation(s)
- Ankit Udai
- Applied Quantum Mechanics Laboratory, Indian Institute of Technology; Bombay, Powai, Mumbai 400076, India
| | - Anthony Aiello
- Solid-State Electronics Laboratory, Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, Michigan 48109-2122, United States
| | - Tarni Aggarwal
- Applied Quantum Mechanics Laboratory, Indian Institute of Technology; Bombay, Powai, Mumbai 400076, India
| | - Dipankar Saha
- Applied Quantum Mechanics Laboratory, Indian Institute of Technology; Bombay, Powai, Mumbai 400076, India
| | - Pallab Bhattacharya
- Solid-State Electronics Laboratory, Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, Michigan 48109-2122, United States
| |
Collapse
|
7
|
Han S, Liang X, Qin C, Gao Y, Song Y, Wang S, Su X, Zhang G, Chen R, Hu J, Jing M, Xiao L, Jia S. Criteria for Assessing the Interlayer Coupling of van der Waals Heterostructures Using Ultrafast Pump-Probe Photoluminescence Spectroscopy. ACS Nano 2021; 15:12966-12974. [PMID: 34314151 DOI: 10.1021/acsnano.1c01787] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
van der Waals (vdW) heterostructures of transition metal dichalcogenides (TMDCs) provide an excellent paradigm for next-generation electronic and optoelectronic applications. However, the reproducible fabrications of vdW heterostructure devices and the boosting of practical applications are severely hindered by their unstable performance, due to the lack of criteria to assess the interlayer coupling in heterostructures. Here we propose a physical model involving ultrafast electron transfer in the heterostructures and provide two criteria, η (the ratio of the transferred electrons to the total excited electrons) and ζ (the relative photoluminescence variation), to evaluate the interlayer coupling by considering the electron transfer in TMDC heterostructures and numerically simulating the corresponding rate equations. We have proved the effectiveness and robustness of two criteria by measuring the pump-probe photoluminescence intensity of monolayer WS2 in the WS2/WSe2 heterostructures. During thermal annealing of WS2/WSe2, ζ varies from negative to positive values and η changes between 0 and 4.5 × 10-3 as the coupling strength enhanced; both of them can well characterize the tuning of interlayer coupling. We also design a scheme to image the interlayer coupling by performing PL imaging at two time delays. Our scheme offers powerful criteria to assess the interlayer coupling in TMDC heterostructures, offering opportunities for the implementation of vdW heterostructures for broadband and high-performance electronic and optoelectronic applications.
Collapse
Affiliation(s)
- Shuangping Han
- State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Laser Spectroscopy, Shanxi University, Taiyuan, Shanxi 030006, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
| | - Xilong Liang
- State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Laser Spectroscopy, Shanxi University, Taiyuan, Shanxi 030006, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
| | - Chengbing Qin
- State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Laser Spectroscopy, Shanxi University, Taiyuan, Shanxi 030006, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
| | - Yan Gao
- Department of Physics, Shanxi Datong University, Datong, Shanxi 037009, China
| | - Yunrui Song
- State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Laser Spectroscopy, Shanxi University, Taiyuan, Shanxi 030006, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
| | - Shen Wang
- College of Physics and Electronics Engineering, Shanxi University, Taiyuan, Shanxi 030006, China
| | - Xingliang Su
- College of Physics and Electronics Engineering, Shanxi University, Taiyuan, Shanxi 030006, China
| | - Guofeng Zhang
- State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Laser Spectroscopy, Shanxi University, Taiyuan, Shanxi 030006, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
| | - Ruiyun Chen
- State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Laser Spectroscopy, Shanxi University, Taiyuan, Shanxi 030006, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
| | - Jianyong Hu
- State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Laser Spectroscopy, Shanxi University, Taiyuan, Shanxi 030006, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
| | - Mingyong Jing
- State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Laser Spectroscopy, Shanxi University, Taiyuan, Shanxi 030006, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
| | - Liantuan Xiao
- State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Laser Spectroscopy, Shanxi University, Taiyuan, Shanxi 030006, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
| | - Suotang Jia
- State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Laser Spectroscopy, Shanxi University, Taiyuan, Shanxi 030006, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
| |
Collapse
|
8
|
Yang G, Yang C, Chen Y, Yu B, Bi Y, Liao J, Li H, Wang H, Wang Y, Liu Z, Gan Z, Yuan Q, Wang Y, Xia J, Wang P. Direct Imaging of Integrated Circuits in CPU with 60 nm Super-Resolution Optical Microscope. Nano Lett 2021; 21:3887-3893. [PMID: 33904733 DOI: 10.1021/acs.nanolett.1c00403] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Far-field super-resolution optical microscopies have achieved incredible success in life science for visualization of vital nanostructures organized in single cells. However, such resolution power has been much less extended to material science for inspection of human-made ultrafine nanostructures, simply because the current super-resolution optical microscopies modalities are rarely applicable to nonfluorescent samples or unlabeled systems. Here, we report an antiphase demodulation pump-probe (DPP) super-resolution microscope for direct optical inspection of integrated circuits (ICs) with a lateral resolution down to 60 nm. Because of the strong pump-probe (PP) signal from copper, we performed label-free super-resolution imaging of multilayered copper interconnects on a small central processing unit (CPU) chip. The label-free super-resolution DPP optical microscopy opens possibilities for easy, fast, and large-scale electronic inspection in the whole pipeline chain for designing and manufacturing ICs.
Collapse
Affiliation(s)
- Guang Yang
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
- MoE Key Laboratory for Biomedical Photonics, Collaborative Innovation Center for Biomedical Engineering, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Chi Yang
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
- MoE Key Laboratory for Biomedical Photonics, Collaborative Innovation Center for Biomedical Engineering, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Yage Chen
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
- MoE Key Laboratory for Biomedical Photonics, Collaborative Innovation Center for Biomedical Engineering, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Boyu Yu
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
- MoE Key Laboratory for Biomedical Photonics, Collaborative Innovation Center for Biomedical Engineering, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Yali Bi
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
- MoE Key Laboratory for Biomedical Photonics, Collaborative Innovation Center for Biomedical Engineering, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Jiangshan Liao
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
- MoE Key Laboratory for Biomedical Photonics, Collaborative Innovation Center for Biomedical Engineering, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Haozheng Li
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
- MoE Key Laboratory for Biomedical Photonics, Collaborative Innovation Center for Biomedical Engineering, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Hong Wang
- Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Yuxi Wang
- Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Ziyu Liu
- Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Zongsong Gan
- Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Quan Yuan
- Institute of Chemical Biology and Nanomedicine, State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China
| | - Yi Wang
- Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Jinsong Xia
- Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Ping Wang
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
- MoE Key Laboratory for Biomedical Photonics, Collaborative Innovation Center for Biomedical Engineering, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| |
Collapse
|
9
|
Kim J, Carnemolla EG, DeVault C, Shaltout AM, Faccio D, Shalaev VM, Kildishev AV, Ferrera M, Boltasseva A. Dynamic Control of Nanocavities with Tunable Metal Oxides. Nano Lett 2018; 18:740-746. [PMID: 29283583 DOI: 10.1021/acs.nanolett.7b03919] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Fabry-Pérot metal-insulator-metal (MIM) nanocavities are widely used in nanophotonic applications due to their extraordinary electromagnetic properties and deeply subwavelength dimensions. However, the spectral response of nanocavities is usually controlled by the spatial separation between the two reflecting mirrors and the spacer's refractive index. Here, we demonstrate static and dynamic control of Fabry-Pérot nanocavities by inserting a plasmonic metasurface, as a passive element, and a gallium doped-zinc oxide (Ga:ZnO) layer as a dynamically tunable component within the nanocavities' spacer. Specifically, by changing the design of the silver (Ag) metasurface one can "statically" tailor the nanocavity response, tuning the resonance up to 200 nm. To achieve the dynamic tuning, we utilize the large nonlinear response of the Ga:ZnO layer near the epsilon near zero wavelength to enable effective subpicosecond (<400 fs) optical modulation (80%) at reasonably low pump fluence levels (9 mJ/cm2). We demonstrate a 15 nm red shift of a near-infrared Fabry-Pérot resonance (λ ≅ 1.16 μm) by using a degenerate pump probe technique. We also study the carrier dynamics of Ga:ZnO under intraband photoexcitation via the electronic band structure calculated from first-principles density functional method. This work provides a versatile approach to design metal nanocavities by utilizing both the phase variation with plasmonic metasurfaces and the strong nonlinear response of metal oxides. Tailorable and dynamically controlled nanocavities could pave the way to the development of the next generation of ultrafast nanophotonic devices.
Collapse
Affiliation(s)
- Jongbum Kim
- School of Electrical and Computer Engineering and Birck Nanotechnology Center, Purdue University , West Lafayette, Indiana 47907, United States
- Institute for Research in Electronics and Applied Physics, University of Maryland , College Park, Maryland 20742, United States
| | - Enrico G Carnemolla
- Institute of Photonics and Quantum Sciences, Heriot-Watt University , SUPA, Edinburg, Scotland EH14 4AS, United Kingdom
| | - Clayton DeVault
- Department of Physics and Astronomy and Birck Nanotechnology Center, Purdue University , West Lafayette, Indiana 47909, United States
| | - Amr M Shaltout
- School of Electrical and Computer Engineering and Birck Nanotechnology Center, Purdue University , West Lafayette, Indiana 47907, United States
| | - Daniele Faccio
- Institute of Photonics and Quantum Sciences, Heriot-Watt University , SUPA, Edinburg, Scotland EH14 4AS, United Kingdom
| | - Vladimir M Shalaev
- School of Electrical and Computer Engineering and Birck Nanotechnology Center, Purdue University , West Lafayette, Indiana 47907, United States
| | - Alexander V Kildishev
- School of Electrical and Computer Engineering and Birck Nanotechnology Center, Purdue University , West Lafayette, Indiana 47907, United States
| | - Marcello Ferrera
- Institute of Photonics and Quantum Sciences, Heriot-Watt University , SUPA, Edinburg, Scotland EH14 4AS, United Kingdom
| | - Alexandra Boltasseva
- School of Electrical and Computer Engineering and Birck Nanotechnology Center, Purdue University , West Lafayette, Indiana 47907, United States
| |
Collapse
|
10
|
Granitzka PW, Jal E, Le Guyader L, Savoini M, Higley DJ, Liu T, Chen Z, Chase T, Ohldag H, Dakovski GL, Schlotter WF, Carron S, Hoffman MC, Gray AX, Shafer P, Arenholz E, Hellwig O, Mehta V, Takahashi YK, Wang J, Fullerton EE, Stöhr J, Reid AH, Dürr HA. Magnetic Switching in Granular FePt Layers Promoted by Near-Field Laser Enhancement. Nano Lett 2017; 17:2426-2432. [PMID: 28272897 DOI: 10.1021/acs.nanolett.7b00052] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Light-matter interaction at the nanoscale in magnetic materials is a topic of intense research in view of potential applications in next-generation high-density magnetic recording. Laser-assisted switching provides a pathway for overcoming the material constraints of high-anisotropy and high-packing density media, though much about the dynamics of the switching process remains unexplored. We use ultrafast small-angle X-ray scattering at an X-ray free-electron laser to probe the magnetic switching dynamics of FePt nanoparticles embedded in a carbon matrix following excitation by an optical femtosecond laser pulse. We observe that the combination of laser excitation and applied static magnetic field, 1 order of magnitude smaller than the coercive field, can overcome the magnetic anisotropy barrier between "up" and "down" magnetization, enabling magnetization switching. This magnetic switching is found to be inhomogeneous throughout the material with some individual FePt nanoparticles neither switching nor demagnetizing. The origin of this behavior is identified as the near-field modification of the incident laser radiation around FePt nanoparticles. The fraction of not-switching nanoparticles is influenced by the heat flow between FePt and a heat-sink layer.
Collapse
Affiliation(s)
- Patrick W Granitzka
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory , 2575 Sand Hill Road, Menlo Park, California 94025, United States
- van der Waals-Zeeman Institute, University of Amsterdam , 1018XE Amsterdam, The Netherlands
| | - Emmanuelle Jal
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory , 2575 Sand Hill Road, Menlo Park, California 94025, United States
| | - Loïc Le Guyader
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory , 2575 Sand Hill Road, Menlo Park, California 94025, United States
- Spectroscopy and Coherent Scattering Instrument, European XFEL GmbH , Holzkoppel 4, 22869 Schenefeld, Germany
| | - Matteo Savoini
- Institute for Quantum Electronics, Eidgenössische Technische Hochschule (ETH) Zürich , Auguste-Piccard-Hof 1, 8093 Zürich, Switzerland
| | - Daniel J Higley
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory , 2575 Sand Hill Road, Menlo Park, California 94025, United States
| | - Tianmin Liu
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory , 2575 Sand Hill Road, Menlo Park, California 94025, United States
| | - Zhao Chen
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory , 2575 Sand Hill Road, Menlo Park, California 94025, United States
| | - Tyler Chase
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory , 2575 Sand Hill Road, Menlo Park, California 94025, United States
| | | | | | | | | | | | - Alexander X Gray
- Department of Physics, Temple University , 1925 N. 12th Street, Philadelphia, Pennsylvania 19122, United States
| | - Padraic Shafer
- Advanced Light Source, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
| | - Elke Arenholz
- Advanced Light Source, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
| | - Olav Hellwig
- San Jose Research Center, HGST a Western Digital Company, 3403 Yerba Buena Road, San Jose, California 95135, United States
| | - Virat Mehta
- San Jose Research Center, HGST a Western Digital Company, 3403 Yerba Buena Road, San Jose, California 95135, United States
| | - Yukiko K Takahashi
- Magnetic Materials Unit, National Institute for Materials Science , Tsukuba 305-0047, Japan
| | - Jian Wang
- Magnetic Materials Unit, National Institute for Materials Science , Tsukuba 305-0047, Japan
| | - Eric E Fullerton
- Center for Memory and Recording Research, University of California San Diego , 9500 Gilman Drive, La Jolla, California 92093-0401, United States
| | - Joachim Stöhr
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory , 2575 Sand Hill Road, Menlo Park, California 94025, United States
| | - Alexander H Reid
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory , 2575 Sand Hill Road, Menlo Park, California 94025, United States
| | - Hermann A Dürr
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory , 2575 Sand Hill Road, Menlo Park, California 94025, United States
| |
Collapse
|
11
|
Valley DT, Ferry VE, Flannigan DJ. Imaging Intra- and Interparticle Acousto-plasmonic Vibrational Dynamics with Ultrafast Electron Microscopy. Nano Lett 2016; 16:7302-7308. [PMID: 27797209 DOI: 10.1021/acs.nanolett.6b03975] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
We report real-space, time-resolved imaging of coherently excited acoustic phonon modes in plasmonic nanoparticles via femtosecond electron imaging with an ultrafast electron microscope. The particles studied were cetyl trimethylammonium bromide stabilized Au nanorods (40 × 120 nm), and the particular specimen configurations for which photoinduced vibrational modes were visualized consisted of a single, isolated nanocrystal and a cluster of four irregularly arranged and randomly oriented particles, all supported on an amorphous Si3N4 membrane. In both configurations, we are able to resolve discrete intraparticle acoustic phonon modes via diffraction-contrast modulation with bright-field femtosecond electron imaging. For the single nanorod, we spatiotemporally mapped the intraparticle vibrational energy distribution and decay times. With Fourier filtering, acoustic phonons ranging from 4 to 30 GHz (250 to 33 ps periods, respectively) were visualized, corresponding to bending, extensional, and higher-order modes. Furthermore, heterogeneously distributed intraparticle decay times, ranging from 3 to 10 ns, were spatially mapped, indicating a strong dependence on coupling of the mode to the underlying substrate. For a cluster of four randomly oriented nanorods, we are able to image acoustic phonon modes that are strongly localized to particular particle-particle contact regions within the aggregate. A vibrational mode occurring at 27 GHz (37 ps period) was observed to occur at a 10 nm side-to-end contact region, with other intraparticle points at distances of 20 and 50 nm from the region showing no such dynamics, although the initial few-picosecond diffraction-contrast response was observed changing sign in moving from the end to the center of the particle. Excellent agreement is found between the spatiotemporally mapped vibrational-mode symmetries and finite-element simulations of supported modes in a polymer-coated Au nanorod supported on a Si3N4 membrane. This experiment resolves both the structure and dynamic properties of the plasmonic assembly, providing insight into the characteristics of complex plasmonic assemblies that ultimately determine their response to ultrafast excitation.
Collapse
Affiliation(s)
- David T Valley
- Department of Chemical Engineering and Materials Science, University of Minnesota , 421 Washington Avenue SE, Minneapolis, Minnesota 55455, United States
| | - Vivian E Ferry
- Department of Chemical Engineering and Materials Science, University of Minnesota , 421 Washington Avenue SE, Minneapolis, Minnesota 55455, United States
| | - David J Flannigan
- Department of Chemical Engineering and Materials Science, University of Minnesota , 421 Washington Avenue SE, Minneapolis, Minnesota 55455, United States
| |
Collapse
|
12
|
Wang K, Szydłowska BM, Wang G, Zhang X, Wang JJ, Magan JJ, Zhang L, Coleman JN, Wang J, Blau WJ. Ultrafast Nonlinear Excitation Dynamics of Black Phosphorus Nanosheets from Visible to Mid-Infrared. ACS Nano 2016; 10:6923-6932. [PMID: 27281449 DOI: 10.1021/acsnano.6b02770] [Citation(s) in RCA: 93] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The recent progress on black phosphorus makes it a promising candidate material for broadband nanophotonic devices, especially operating in the mid-infrared spectral region. Here, the excited carrier dynamics and nonlinear optical response of unoxidized black phosphorus nanosheets and their wavelength dependence were systematically studied from 800 nm to 2.1 μm. The wavelength-dependent relaxation times of black phosphorus nanosheets are determined to be 360 fs to 1.36 ps with photon energies from 1.55 to 0.61 eV. In a comparative study with graphene, we found that black phosphorus has a faster carrier relaxation in near- and mid-infrared region. With regard to nonlinear optical absorption, the response of black phosphorus significantly increases from near- to mid-infrared, and black phosphorus is also confirmed to be better as saturable absorber to MoS2 in infrared region.
Collapse
Affiliation(s)
- Kangpeng Wang
- School of Physics and CRANN, Trinity College Dublin , Dublin 2, Ireland
| | | | - Gaozhong Wang
- School of Physics and CRANN, Trinity College Dublin , Dublin 2, Ireland
| | - Xiaoyan Zhang
- Key Laboratory of Materials for High-Power Laser, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences , Shanghai 201800, China
| | - Jing Jing Wang
- School of Physics and CRANN, Trinity College Dublin , Dublin 2, Ireland
| | - John J Magan
- School of Physics and CRANN, Trinity College Dublin , Dublin 2, Ireland
| | - Long Zhang
- Key Laboratory of Materials for High-Power Laser, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences , Shanghai 201800, China
| | | | - Jun Wang
- Key Laboratory of Materials for High-Power Laser, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences , Shanghai 201800, China
- State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences , Shanghai 201800, China
| | - Werner J Blau
- School of Physics and CRANN, Trinity College Dublin , Dublin 2, Ireland
| |
Collapse
|
13
|
Jadidi MM, König-Otto JC, Winnerl S, Sushkov AB, Drew HD, Murphy TE, Mittendorff M. Nonlinear Terahertz Absorption of Graphene Plasmons. Nano Lett 2016; 16:2734-2738. [PMID: 26978242 DOI: 10.1021/acs.nanolett.6b00405] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Subwavelength graphene structures support localized plasmonic resonances in the terahertz and mid-infrared spectral regimes. The strong field confinement at the resonant frequency is predicted to significantly enhance the light-graphene interaction, which could enable nonlinear optics at low intensity in atomically thin, subwavelength devices. To date, the nonlinear response of graphene plasmons and their energy loss dynamics have not been experimentally studied. We measure and theoretically model the terahertz nonlinear response and energy relaxation dynamics of plasmons in graphene nanoribbons. We employ a terahertz pump-terahertz probe technique at the plasmon frequency and observe a strong saturation of plasmon absorption followed by a 10 ps relaxation time. The observed nonlinearity is enhanced by 2 orders of magnitude compared to unpatterned graphene with no plasmon resonance. We further present a thermal model for the nonlinear plasmonic absorption that supports the experimental results. The model shows that the observed strong linearity is caused by an unexpected red shift of plasmon resonance together with a broadening and weakening of the resonance caused by the transient increase in electron temperature. The model further predicts that even greater resonant enhancement of the nonlinear response can be expected in high-mobility graphene, suggesting that nonlinear graphene plasmonic devices could be promising candidates for nonlinear optical processing.
Collapse
Affiliation(s)
- Mohammad M Jadidi
- Institute for Research in Electronics and Applied Physics, University of Maryland , College Park, Maryland 20742, United States
| | - Jacob C König-Otto
- Helmholtz-Zentrum Dresden-Rossendorf , P.O. Box 510119, 01314 Dresden, Germany
- Technische Universität Dresden , 01062 Dresden, Germany
| | - Stephan Winnerl
- Helmholtz-Zentrum Dresden-Rossendorf , P.O. Box 510119, 01314 Dresden, Germany
| | - Andrei B Sushkov
- Center for Nanophysics and Advanced Materials, University of Maryland , College Park, Maryland 20742, United States
| | - H Dennis Drew
- Center for Nanophysics and Advanced Materials, University of Maryland , College Park, Maryland 20742, United States
| | - Thomas E Murphy
- Institute for Research in Electronics and Applied Physics, University of Maryland , College Park, Maryland 20742, United States
| | - Martin Mittendorff
- Institute for Research in Electronics and Applied Physics, University of Maryland , College Park, Maryland 20742, United States
| |
Collapse
|
14
|
Della Picca F, Berte R, Rahmani M, Albella P, Bujjamer JM, Poblet M, Cortés E, Maier SA, Bragas AV. Tailored Hypersound Generation in Single Plasmonic Nanoantennas. Nano Lett 2016; 16:1428-1434. [PMID: 26814800 DOI: 10.1021/acs.nanolett.5b04991] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Ultrashort laser pulses impinging on a plasmonic nanostructure trigger a highly dynamic scenario in the interplay of electronic relaxation with lattice vibrations, which can be experimentally probed via the generation of coherent phonons. In this Letter, we present studies of hypersound generation in the range of a few to tens of gigahertz on single gold plasmonic nanoantennas, which have additionally been subjected to predesigned mechanical constraints via silica bridges. Using these hybrid gold/silica nanoantennas, we demonstrate experimentally and via numerical simulations how mechanical constraints allow control over their vibrational mode spectrum. Degenerate pump-probe techniques with double modulation are performed in order to detect the small changes produced in the probe transmission by the mechanical oscillations of these single nanoantennas.
Collapse
Affiliation(s)
- Fabricio Della Picca
- Laboratorio de Electrónica Cuántica, Departmento de Física, FCEN-IFIBA CONICET, Universidad de Buenos Aires , Intendente Güiraldes 2160, C1428EGA, Buenos Aires, Argentina
| | - Rodrigo Berte
- The Blackett Laboratory, Department of Physics, Imperial College London , London SW7 2AZ, United Kingdom
- CAPES Foundation, Ministry of Education of Brazil , Brasilia, DF 70040-020, Brazil
| | - Mohsen Rahmani
- The Blackett Laboratory, Department of Physics, Imperial College London , London SW7 2AZ, United Kingdom
| | - Pablo Albella
- The Blackett Laboratory, Department of Physics, Imperial College London , London SW7 2AZ, United Kingdom
| | - Juan M Bujjamer
- Laboratorio de Electrónica Cuántica, Departmento de Física, FCEN-IFIBA CONICET, Universidad de Buenos Aires , Intendente Güiraldes 2160, C1428EGA, Buenos Aires, Argentina
| | - Martín Poblet
- Laboratorio de Electrónica Cuántica, Departmento de Física, FCEN-IFIBA CONICET, Universidad de Buenos Aires , Intendente Güiraldes 2160, C1428EGA, Buenos Aires, Argentina
| | - Emiliano Cortés
- The Blackett Laboratory, Department of Physics, Imperial College London , London SW7 2AZ, United Kingdom
| | - Stefan A Maier
- The Blackett Laboratory, Department of Physics, Imperial College London , London SW7 2AZ, United Kingdom
| | - Andrea V Bragas
- Laboratorio de Electrónica Cuántica, Departmento de Física, FCEN-IFIBA CONICET, Universidad de Buenos Aires , Intendente Güiraldes 2160, C1428EGA, Buenos Aires, Argentina
| |
Collapse
|
15
|
Gilbertson AM, Francescato Y, Roschuk T, Shautsova V, Chen Y, Sidiropoulos TPH, Hong M, Giannini V, Maier SA, Cohen LF, Oulton RF. Plasmon-induced optical anisotropy in hybrid graphene-metal nanoparticle systems. Nano Lett 2015; 15:3458-3464. [PMID: 25915785 DOI: 10.1021/acs.nanolett.5b00789] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Hybrid plasmonic metal-graphene systems are emerging as a class of optical metamaterials that facilitate strong light-matter interactions and are of potential importance for hot carrier graphene-based light harvesting and active plasmonic applications. Here we use femtosecond pump-probe measurements to study the near-field interaction between graphene and plasmonic gold nanodisk resonators. By selectively probing the plasmon-induced hot carrier dynamics in samples with tailored graphene-gold interfaces, we show that plasmon-induced hot carrier generation in the graphene is dominated by direct photoexcitation with minimal contribution from charge transfer from the gold. The strong near-field interaction manifests as an unexpected and long-lived extrinsic optical anisotropy. The observations are explained by the action of highly localized plasmon-induced hot carriers in the graphene on the subresonant polarizability of the disk resonator. Because localized hot carrier generation in graphene can be exploited to drive electrical currents, plasmonic metal-graphene nanostructures present opportunities for novel hot carrier device concepts.
Collapse
Affiliation(s)
- Adam M Gilbertson
- †Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2BZ, United Kingdom
| | - Yan Francescato
- †Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2BZ, United Kingdom
| | - Tyler Roschuk
- †Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2BZ, United Kingdom
| | - Viktoryia Shautsova
- †Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2BZ, United Kingdom
| | - Yiguo Chen
- †Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2BZ, United Kingdom
- ‡Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive, 117576 Singapore
| | | | - Minghui Hong
- ‡Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive, 117576 Singapore
| | - Vincenzo Giannini
- †Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2BZ, United Kingdom
| | - Stefan A Maier
- †Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2BZ, United Kingdom
| | - Lesley F Cohen
- †Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2BZ, United Kingdom
| | - Rupert F Oulton
- †Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2BZ, United Kingdom
| |
Collapse
|
16
|
Bohinski T, Moore Tibbetts K, Tarazkar M, Romanov DA, Matsika S, Levis RJ. Strong Field Adiabatic Ionization Prepares a Launch State for Coherent Control. J Phys Chem Lett 2014; 5:4305-4309. [PMID: 26273978 DOI: 10.1021/jz502313f] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We demonstrate that excitation of acetophenone with a strong field, near-infrared femtosecond pulse (1150-1500 nm) results in adiabatic ionization, producing acetophenone radical cation in the ground electronic state. The time-resolved transients of the parent and fragment ions probed with a weak 790 nm pulse reveal an order of magnitude enhancement of the peak-to-peak amplitude oscillations, ∼ 100 fs longer coherence time, and an order of magnitude increase in the ratio of parent to fragment ions in comparison with nonadiabatic ionization with a strong field 790 nm pulse. Equation of motion coupled cluster and classical wavepacket trajectory calculations support the mechanism wherein the probe pulse excites a wavepacket on the ground surface D0 to the excited D2 surface at a delay of 325 fs, resulting in dissociation to the benzoyl ion. Direct population transfer to the D2 state within the duration of a 1370 nm pump pulse eliminates wavepacket oscillation on the D0 state.
Collapse
Affiliation(s)
- Timothy Bohinski
- †Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122, United States
- ‡Center for Advanced Photonics Research, Temple University, Philadelphia, Pennsylvania 19122, United States
| | - Katharine Moore Tibbetts
- †Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122, United States
- ‡Center for Advanced Photonics Research, Temple University, Philadelphia, Pennsylvania 19122, United States
| | - Maryam Tarazkar
- †Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122, United States
- ‡Center for Advanced Photonics Research, Temple University, Philadelphia, Pennsylvania 19122, United States
| | - Dmitri A Romanov
- ‡Center for Advanced Photonics Research, Temple University, Philadelphia, Pennsylvania 19122, United States
- §Department of Physics, Temple University, Philadelphia, Pennsylvania 19122, United States
| | - Spiridoula Matsika
- †Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122, United States
| | - Robert J Levis
- †Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122, United States
- ‡Center for Advanced Photonics Research, Temple University, Philadelphia, Pennsylvania 19122, United States
| |
Collapse
|
17
|
Li X, Feng D, Tong H, Jia T, Deng L, Sun Z, Xu Z. Hole Surface Trapping Dynamics Directly Monitored by Electron Spin Manipulation in CdS Nanocrystals. J Phys Chem Lett 2014; 5:4310-4316. [PMID: 26273979 DOI: 10.1021/jz502340w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
A new detection technique, pump-spin orientation-probe ultrafast spectroscopy, is developed to study the hole trapping dynamics in colloidal CdS nanocrystals. The hole surface trapping process spatially separates the electron-hole pairs excited by the pump pulse, leaves the core negatively charged, and thus enhances the electron spin signal generated by the orientation pulse. The spin enhancement transients as a function of the pump-orientation delay reveal a fast and a slow hole trapping process with respective time constants of sub-10 ps and sub-100 ps, orders of magnitude faster than that of carrier recombination. The power dependence of hole trapping dynamics elucidates the saturation process and relative number of traps, and suggests that there are three subpopulations of nanoparticles related to hole surface trapping, one with the fast trapping pathway only, another with the slow trapping pathway only, and the third with both pathways together.
Collapse
Affiliation(s)
- Xiao Li
- †State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, China
| | - Donghai Feng
- †State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, China
| | - Haifang Tong
- †State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, China
| | - Tianqing Jia
- †State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, China
| | - Li Deng
- †State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, China
| | - Zhenrong Sun
- †State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, China
| | - Zhizhan Xu
- ‡State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
| |
Collapse
|
18
|
Jensen SA, Mics Z, Ivanov I, Varol HS, Turchinovich D, Koppens FHL, Bonn M, Tielrooij KJ. Competing ultrafast energy relaxation pathways in photoexcited graphene. Nano Lett 2014; 14:5839-45. [PMID: 25247639 DOI: 10.1021/nl502740g] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
For most optoelectronic applications of graphene, a thorough understanding of the processes that govern energy relaxation of photoexcited carriers is essential. The ultrafast energy relaxation in graphene occurs through two competing pathways: carrier-carrier scattering, creating an elevated carrier temperature, and optical phonon emission. At present, it is not clear what determines the dominating relaxation pathway. Here we reach a unifying picture of the ultrafast energy relaxation by investigating the terahertz photoconductivity, while varying the Fermi energy, photon energy and fluence over a wide range. We find that sufficiently low fluence (≲4 μJ/cm(2)) in conjunction with sufficiently high Fermi energy (≳0.1 eV) gives rise to energy relaxation that is dominated by carrier-carrier scattering, which leads to efficient carrier heating. Upon increasing the fluence or decreasing the Fermi energy, the carrier heating efficiency decreases, presumably due to energy relaxation that becomes increasingly dominated by phonon emission. Carrier heating through carrier-carrier scattering accounts for the negative photoconductivity for doped graphene observed at terahertz frequencies. We present a simple model that reproduces the data for a wide range of Fermi levels and excitation energies and allows us to qualitatively assess how the branching ratio between the two distinct relaxation pathways depends on excitation fluence and Fermi energy.
Collapse
Affiliation(s)
- S A Jensen
- Max Planck Institute for Polymer Research , Ackermannweg 10, 55128 Mainz, Germany
| | | | | | | | | | | | | | | |
Collapse
|
19
|
Belshaw L, Calegari F, Duffy MJ, Trabattoni A, Poletto L, Nisoli M, Greenwood JB. Observation of Ultrafast Charge Migration in an Amino Acid. J Phys Chem Lett 2012; 3:3751-3754. [PMID: 26291106 DOI: 10.1021/jz3016028] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We present the first direct measurement of ultrafast charge migration in a biomolecular building block - the amino acid phenylalanine. Using an extreme ultraviolet pulse of 1.5 fs duration to ionize molecules isolated in the gas phase, the location of the resulting hole was probed by a 6 fs visible/near-infrared pulse. By measuring the yield of a doubly charged ion as a function of the delay between the two pulses, the positive hole was observed to migrate to one end of the cation within 30 fs. This process is likely to originate from even faster coherent charge oscillations in the molecule being dephased by bond stretching which eventually localizes the final position of the charge. This demonstration offers a clear template for observing and controlling this phenomenon in the future.
Collapse
Affiliation(s)
- Louise Belshaw
- †Centre for Plasma Physics, School of Maths and Physics, Queen's University Belfast, BT7 1NN, United Kingdom
| | - Francesca Calegari
- ‡Politecnico di Milano, Department of Physics, Institute of Photonics and Nanotechnologies, CNR-IFN, I-20133 Milan, Italy
| | - Martin J Duffy
- †Centre for Plasma Physics, School of Maths and Physics, Queen's University Belfast, BT7 1NN, United Kingdom
| | - Andrea Trabattoni
- ‡Politecnico di Milano, Department of Physics, Institute of Photonics and Nanotechnologies, CNR-IFN, I-20133 Milan, Italy
| | - Luca Poletto
- §Institute of Photonics and Nanotechnologies, CNR-IFN, I-35131 Padua, Italy
| | - Mauro Nisoli
- ‡Politecnico di Milano, Department of Physics, Institute of Photonics and Nanotechnologies, CNR-IFN, I-20133 Milan, Italy
| | - Jason B Greenwood
- †Centre for Plasma Physics, School of Maths and Physics, Queen's University Belfast, BT7 1NN, United Kingdom
| |
Collapse
|