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Gallop N, Sirbu D, Walker D, Lloyd-Hughes J, Docampo P, Milot RL. Terahertz Emission via Optical Rectification in a Metal-Free Perovskite Crystal. ACS PHOTONICS 2023; 10:4022-4030. [PMID: 38027252 PMCID: PMC10655262 DOI: 10.1021/acsphotonics.3c00918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Indexed: 12/01/2023]
Abstract
We report on the emission of high-intensity pulsed terahertz radiation from the metal-free halide perovskite single crystal methyl-DABCO ammonium iodide (MDNI) under femtosecond illumination. The power and angular dependence of the THz output implicate optical rectification of the 800 nm pump as the mechanism of THz generation. Further characterization finds that, for certain crystal orientations, the angular dependence of THz emission is modulated by phonon resonances attributable to the motion of the methyl-DABCO moiety. At maximum, the THz emission spectrum of MDNI is free from significant phonon resonances, resulting in THz pulses with a temporal width of <900 fs and a peak-to-peak electric field strength of approximately 0.8 kV cm-1-2 orders of magnitude higher than any other reported halide perovskite emitters. Our results point toward metal-free perovskites as a promising new class of THz emitters that brings to bear many of the advantages enjoyed by other halide perovskite materials. In particular, the broad tunability of optoelectronic properties and ease of fabrication of perovskite materials opens up the possibility of further optimizing the THz emission properties within this material class.
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Affiliation(s)
| | - Dumitru Sirbu
- School
of Mathematics, Statistics and Physics, Newcastle University, Newcastle
upon Tyne NE1 7RU, U.K.
| | - David Walker
- Department
of Physics, University of Warwick, Coventry CV4 7AL, U.K.
| | | | - Pablo Docampo
- School
of Mathematics, Statistics and Physics, Newcastle University, Newcastle
upon Tyne NE1 7RU, U.K.
- School
of Chemistry, University of Glasgow, Glasgow G12 8QQ, U.K.
| | - Rebecca L. Milot
- Department
of Physics, University of Warwick, Coventry CV4 7AL, U.K.
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Ilyakov IE, Shishkin BV, Malevich VL, Ponomarev DS, Galiev RR, Pavlov AY, Yachmenev AE, Kovalev SP, Chen M, Akhmedzhanov RA, Khabibullin RA. Efficient optical-to-terahertz conversion in large-area InGaAs photo-Dember emitters with increased indium content. OPTICS LETTERS 2021; 46:3360-3363. [PMID: 34264213 DOI: 10.1364/ol.428599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 06/15/2021] [Indexed: 06/13/2023]
Abstract
In this Letter, optical-to-terahertz (THz) conversion of 800 nm femtosecond laser pulses in large-area bias-free InGaAs emitters based on photo-Dember (PD) and lateral photo-Dember (LPD) effects is experimentally investigated. We use metamorphic buffers to grow sub-micrometer thick InxGa1-xAs layers with indium mole fractions x=0.37, 0.53, and 0.70 on a GaAs substrate. A strong enhancement of THz output energy with an increase of indium content is observed. On the surface of the sample providing the strongest emission (x=0.7), we have fabricated a 1.5cm2 area of asymmetrically shaped metallic grating for LPD emission. This LPD emitter allows achieving high conversion efficiency of 0.24⋅10-3 and a broad generation bandwidth of up to 6 THz. We also demonstrate that there is no significant difference in the conversion efficiency when operating at 1 and 200 kHz repetition rates. Our results show that large-area LPD emitters give a convenient, competitive way to generate intense high-repetition-rate THz pulses.
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Huang Y, Yao Z, He C, Zhu L, Zhang L, Bai J, Xu X. Terahertz surface and interface emission spectroscopy for advanced materials. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:153001. [PMID: 30669133 DOI: 10.1088/1361-648x/ab00c0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Surfaces and interfaces are of particular importance for optoelectronic and photonic materials as they are involved in many physical and chemical processes such as carrier dynamics, charge transfer, chemical bonding, transformation reactions and so on. Terahertz (THz) emission spectroscopy provides a sensitive and nondestructive method for surface or interface analysis of advanced materials ranging from graphene to transition metal dichalcogenides, topological insulators, hybrid perovskites, and mixed-dimensional heterostructures based on 2D materials. In this review paper, we start with the THz radiation mechanisms under ultrafast laser excitation. Then we concentrate on the recent progresses of THz emission spectroscopy on the surface and interface properties of advanced materials, including transient surface photocurrents, surface nonlinear polarization, surface states, interface potential, and gas molecule adsorption/desorption processes. This novel spectroscopic method can not only promote the development of new and compact THz sources, but also provide a nondestructive optical method for surface and interface characterization of photocurrent and nonlinear polarization dynamics of materials.
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Affiliation(s)
- Yuanyuan Huang
- Shaanxi Joint Lab of Graphene, State Key Lab Incubation Base of Photoelectric Technology and Functional Materials, International Collaborative Center on Photoelectric Technology and Nano Functional Materials, Institute of Photonics and Photon-Technology, Northwest University, Xi'an 710069, People's Republic of China
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Huang Y, Zhu L, Zhao Q, Guo Y, Ren Z, Bai J, Xu X. Surface Optical Rectification from Layered MoS 2 Crystal by THz Time-Domain Surface Emission Spectroscopy. ACS APPLIED MATERIALS & INTERFACES 2017; 9:4956-4965. [PMID: 28098966 DOI: 10.1021/acsami.6b13961] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Surface optical rectification was observed from the layered semiconductor molybdenum disulfide (MoS2) crystal via terahertz (THz) time-domain surface emission spectroscopy under linearly polarized femtosecond laser excitation. The radiated THz amplitude of MoS2 has a linear dependence on ever-increasing pump fluence and thus quadratic with the pump electric field, which discriminates from the surface Dember field induced THz radiation in InAs and the transient photocurrent-induced THz generation in graphite. Theoretical analysis based on space symmetry of MoS2 crystal suggests that the underlying mechanism of THz radiation is surface optical rectification under the reflection configuration. This is consistent with the experimental results according to the radiated THz amplitude dependences on azimuthal and incident polarization angles. We also demonstrated the damage threshold of MoS2 due to microscopic bond breaking under the femtosecond laser irradiation, which can be monitored via THz time-domain emission spectroscopy and Raman spectroscopy.
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Affiliation(s)
- Yuanyuan Huang
- Shaanxi Joint Lab of Graphene, State Key Lab Incubation Base of Photoelectric Technology and Functional Materials, International Collaborative Center on Photoelectric Technology and Nano Functional Materials, Institute of Photonics and Photon-Technology, Northwest University , Xi'an 710069, China
| | - Lipeng Zhu
- Shaanxi Joint Lab of Graphene, State Key Lab Incubation Base of Photoelectric Technology and Functional Materials, International Collaborative Center on Photoelectric Technology and Nano Functional Materials, Institute of Photonics and Photon-Technology, Northwest University , Xi'an 710069, China
| | - Qiyi Zhao
- Shaanxi Joint Lab of Graphene, State Key Lab Incubation Base of Photoelectric Technology and Functional Materials, International Collaborative Center on Photoelectric Technology and Nano Functional Materials, Institute of Photonics and Photon-Technology, Northwest University , Xi'an 710069, China
| | - Yaohui Guo
- Shaanxi Joint Lab of Graphene, State Key Lab Incubation Base of Photoelectric Technology and Functional Materials, International Collaborative Center on Photoelectric Technology and Nano Functional Materials, Institute of Photonics and Photon-Technology, Northwest University , Xi'an 710069, China
| | - Zhaoyu Ren
- Shaanxi Joint Lab of Graphene, State Key Lab Incubation Base of Photoelectric Technology and Functional Materials, International Collaborative Center on Photoelectric Technology and Nano Functional Materials, Institute of Photonics and Photon-Technology, Northwest University , Xi'an 710069, China
| | - Jintao Bai
- Shaanxi Joint Lab of Graphene, State Key Lab Incubation Base of Photoelectric Technology and Functional Materials, International Collaborative Center on Photoelectric Technology and Nano Functional Materials, Institute of Photonics and Photon-Technology, Northwest University , Xi'an 710069, China
| | - Xinlong Xu
- Shaanxi Joint Lab of Graphene, State Key Lab Incubation Base of Photoelectric Technology and Functional Materials, International Collaborative Center on Photoelectric Technology and Nano Functional Materials, Institute of Photonics and Photon-Technology, Northwest University , Xi'an 710069, China
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Generation of radially-polarized terahertz pulses for coupling into coaxial waveguides. Sci Rep 2016; 6:38926. [PMID: 27941845 PMCID: PMC5150854 DOI: 10.1038/srep38926] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Accepted: 11/15/2016] [Indexed: 11/24/2022] Open
Abstract
Coaxial waveguides exhibit no dispersion and therefore can serve as an ideal channel for transmission of broadband THz pulses. Implementation of THz coaxial waveguide systems however requires THz beams with radially-polarized distribution. We demonstrate the launching of THz pulses into coaxial waveguides using the effect of THz pulse generation at semiconductor surfaces. We find that the radial transient photo-currents produced upon optical excitation of the surface at normal incidence radiate a THz pulse with the field distribution matching the mode of the coaxial waveguide. In this simple scheme, the optical excitation beam diameter controls the spatial profile of the generated radially-polarized THz pulse and allows us to achieve efficient coupling into the TEM waveguide mode in a hollow coaxial THz waveguide. The TEM quasi-single mode THz waveguide excitation and non-dispersive propagation of a short THz pulse is verified experimentally by time-resolved near-field mapping of the THz field at the waveguide output.
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Wallauer J, Grumber C, Walther M. Mapping the coupling between a photo-induced local dipole and the eigenmodes of a terahertz metamaterial. OPTICS LETTERS 2014; 39:6138-6141. [PMID: 25361298 DOI: 10.1364/ol.39.006138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We demonstrate that eigenmodes of a metamaterial structure at terahertz (THz) frequencies can be excited by photo-generation of localized transient dipoles in the semiconductor substrate. We apply this technique to map the coupling of these dipoles to the resonator's near-field. The characteristic metamaterial resonances appear as peaks in the spectrum of the THz radiation emitted from the resonant structures into the far-field. Recording two-dimensional THz emission maps allows us to reproduce the frequency-dependent spatial profiles of the metamaterial's eigenmodes.
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McBryde D, Barnes ME, Berry SA, Gow P, Beere HE, Ritchie DA, Apostolopoulos V. Fluence and polarisation dependence of GaAs based Lateral Photo-Dember terahertz emitters. OPTICS EXPRESS 2014; 22:3234-3243. [PMID: 24663615 DOI: 10.1364/oe.22.003234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We characterise THz output of lateral photo-Dember (LPD) emitters based on semi-insulating (SI), unannealed and annealed low temperature grown (LTG) GaAs. Saturation of THz pulse power with optical fluence is observed, with unannealed LTG GaAs showing highest saturation fluence at 1.1 ± 0.1 mJ cm(-2). SI-GaAs LPD emitters show a flip in signal polarity with optical fluence that is attributed to THz emission from the metal-semiconductor contact. Variation in optical polarisation affects THz pulse power that is attributed to a local optical excitation near the metal contact.
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