1
|
Michon MA, Chmielniak P, Weber PM, Rose-Petruck C. Two-photon chemistry of tetrahydrofuran in clathrate hydrates. Phys Chem Chem Phys 2024; 26:2568-2579. [PMID: 38170862 DOI: 10.1039/d3cp02607h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
High-lying electronic states hold the potential for new and unusual photochemical reactions. However, for conventional single-photon excitation in the condensed phase, reaching these states is often not possible because the vacuum-ultraviolet (VUV) light required is competitively absorbed by the surrounding matrix rather than the molecule of interest. Here, this hurdle is overcome by leveraging nonresonant two-photon absorption (2PA) at 265 nm to achieve preferential photolysis of tetrahydrofuran (THF) trapped within a clathrate hydrate network at 77 K. Electron spin resonance (ESR) spectroscopy enables direct observation and identification of otherwise short-lived organic radicals stabilized by the clathrate cages, providing clues into the rapid dynamics that immediately follow photoexcitation. 2PA induces extensive fragmentation of enclathrated THF yielding 1-alkyl, acyl, allyl and methyl radicals-a stark departure from the reactive motifs commonly reported in γ-irradiated hydrates. We speculate on the undetected transient dynamics and explore the potential role of trapped electrons generated from water and THF. This demonstration of nonresonant two-photon chemistry presents an alternative approach to targeted condensed phase photochemistry in the VUV energy range.
Collapse
Affiliation(s)
- Michael A Michon
- Department of Chemistry, Brown University, Providence, 02912, Rhode Island, USA.
| | - Pawel Chmielniak
- Department of Chemistry, Brown University, Providence, 02912, Rhode Island, USA.
| | - Peter M Weber
- Department of Chemistry, Brown University, Providence, 02912, Rhode Island, USA.
| | | |
Collapse
|
2
|
Cui Z, Sun M, Liu D, Zhu J. High-peak-power picosecond deep-UV laser sources. OPTICS EXPRESS 2022; 30:43354-43370. [PMID: 36523035 DOI: 10.1364/oe.474513] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 10/14/2022] [Indexed: 06/17/2023]
Abstract
Ultrafast deep-UV laser sources have extensive applications across a wide number of fields, whether biomedicine, photolithography, industrial processing, or state-of-the-art scientific research. However, it has been challenging to obtain deep-UV laser sources with high conversion efficiency and output peak power. Here, we simultaneously demonstrated high-peak-power picosecond deep-UV laser sources at two typical wavebands of 263.2 and 210.5 nm via the efficient fourth- and fifth-harmonic generation. The highest peak power of 263.2 and 210.5 nm laser radiations were up to 2.13 GW (6.72 ps) and 1.38 GW (5.08 ps). The overall conversion efficiencies from the fundamental wave to the fourth and fifth harmonic were up to 42.9% and 28.8%, respectively. The demonstrated results represent the highest conversion efficiencies and output peak powers of picosecond deep-UV laser sources at present to our knowledge. Additionally, we also systematically characterized the deep-UV optical properties of typical birefringent and nonlinear borate crystals, including α-BaB2O4, β-BaB2O4, LiB3O5, and CsLiB6O10 crystals. The experiments and obtained numerous new optical data in this work will contribute to the generation of ultrahigh-peak-power deep-UV and vacuum-UV laser sources and crucial applications in both science and industry, such as high-energy-density physics, material science, and laser machining.
Collapse
|
3
|
Labra-Vázquez P, Bocé M, Tassé M, Mallet-Ladeira S, Lacroix PG, Farfán N, Malfant I. Chemical and photochemical behavior of ruthenium nitrosyl complexes with terpyridine ligands in aqueous media. Dalton Trans 2020; 49:3138-3154. [PMID: 32076692 DOI: 10.1039/c9dt04832d] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The synthesis and behavior in water of a set of various cis(Cl,Cl)-[R-tpyRuCl2(NO)](PF6) and trans(Cl,Cl)-[R-tpyRuCl2(NO)](PF6) (R = fluorenyl, phenyl, thiophenyl; tpy = 2,2':6',2''-terpyridine) complexes are presented. In any case, one chlorido ligand is substituted by a hydroxo ligand and the final species arises as a single trans(NO,OH) isomer, whatever the nature of the starting cis/trans(Cl,Cl) complexes. Six X-ray crystal structures are presented for cis(Cl,Cl)-[thiophenyl-tpyRuCl2(NO)](PF6) (cis-3a), trans(Cl,Cl)-[thiophenyl-tpyRuCl2(NO)](PF6) (trans-3a), trans(NO,OH)-[phenyl-tpyRu(Cl)(OH)(NO)](PF6) (4a), trans(NO,OH)-[thiophenyl-tpyRu(Cl)(OH)(NO)](PF6) (4b), trans(NO,OEt)-[phenyl-tpyRu(Cl)(OEt)(NO)](PF6) (5a), and trans(NO,OH)-[phenyl-tpyRu(Cl)(OEt)(NO)](PF6) (5b) compounds. The different cis/trans(Cl,Cl) complexes exhibit an intense low-lying transition in the λ = 330-390 nm range, which appears to be slightly blue-shifted after Cl → OH substitution. In water, both cis/trans(Cl,Cl) isomers are converted to a single trans(NO,OH) isomer in which one chlorido- is replaced by one hydroxo-ligand, which avoids tedious separation workout. The water stable trans(NO,OH)-species all release NO with quantum yields of 0.010 to 0.075 under irradiation at 365 nm. The properties are discussed with computational analysis performed within the framework of Density Functional Theory.
Collapse
Affiliation(s)
- Pablo Labra-Vázquez
- Laboratoire de Chimie de Coordination du CNRS, 205 route de Narbonne, F-31077, Toulouse, France.
| | | | | | | | | | | | | |
Collapse
|
4
|
Bhattacharyya D, Zhang Y, Elles CG, Bradforth SE. Electronic Structure of Liquid Methanol and Ethanol from Polarization-Dependent Two-Photon Absorption Spectroscopy. J Phys Chem A 2019; 123:5789-5804. [DOI: 10.1021/acs.jpca.9b04040] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Dhritiman Bhattacharyya
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482, United States
| | - Yuyuan Zhang
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482, United States
| | - Christopher G. Elles
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482, United States
| | - Stephen E. Bradforth
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482, United States
| |
Collapse
|
5
|
Luo L, Zhang Q, Luo Y, He Z, Tian X, Battaglia G. Thermosensitive nanocomposite gel for intra-tumoral two-photon photodynamic therapy. J Control Release 2019; 298:99-109. [DOI: 10.1016/j.jconrel.2019.01.019] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2018] [Revised: 01/03/2019] [Accepted: 01/15/2019] [Indexed: 12/25/2022]
|
6
|
Marble CB, Clary JE, Noojin GD, O'Connor SP, Nodurft DT, Wharmby AW, Rockwell BA, Scully MO, Yakovlev VV. Z-scan measurements of water from 1150 to 1400 nm. OPTICS LETTERS 2018; 43:4196-4199. [PMID: 30160750 DOI: 10.1364/ol.43.004196] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Accepted: 07/30/2018] [Indexed: 06/08/2023]
Abstract
Understanding the nonlinear properties of water is essential for laser surgery applications, as well as understanding supercontinuum generation in water. Unfortunately, the nonlinear properties of water for wavelengths longer than 1064 nm are poorly understood. We extend the application of the Z-scan technique in water to determine its nonlinear refractive index (n2) and nonlinear absorption (β) for wavelengths in the 1150-1400 nm range, where linear absorption is also significant. We observe the wavelength-dependent variation of the nonlinear properties of water around the water absorption band.
Collapse
|
7
|
Ochmann M, Hussain A, von Ahnen I, Cordones AA, Hong K, Lee JH, Ma R, Adamczyk K, Kim TK, Schoenlein RW, Vendrell O, Huse N. UV-Photochemistry of the Disulfide Bond: Evolution of Early Photoproducts from Picosecond X-ray Absorption Spectroscopy at the Sulfur K-Edge. J Am Chem Soc 2018; 140:6554-6561. [PMID: 29771112 DOI: 10.1021/jacs.7b13455] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
We have investigated dimethyl disulfide as the basic moiety for understanding the photochemistry of disulfide bonds, which are central to a broad range of biochemical processes. Picosecond time-resolved X-ray absorption spectroscopy at the sulfur K-edge provides unique element-specific insight into the photochemistry of the disulfide bond initiated by 267 nm femtosecond pulses. We observe a broad but distinct transient induced absorption spectrum which recovers on at least two time scales in the nanosecond range. We employed RASSCF electronic structure calculations to simulate the sulfur-1s transitions of multiple possible chemical species, and identified the methylthiyl and methylperthiyl radicals as the primary reaction products. In addition, we identify disulfur and the CH2S thione as the secondary reaction products of the perthiyl radical that are most likely to explain the observed spectral and kinetic signatures of our experiment. Our study underscores the importance of elemental specificity and the potential of time-resolved X-ray spectroscopy to identify short-lived reaction products in complex reaction schemes that underlie the rich photochemistry of disulfide systems.
Collapse
Affiliation(s)
- Miguel Ochmann
- Department of Physics , University of Hamburg and Max Planck Institute for the Structure and Dynamics of Matter, Center for Free Electron Laser Science , 22761 Hamburg , Germany
| | - Abid Hussain
- Department of Physics , University of Hamburg and Max Planck Institute for the Structure and Dynamics of Matter, Center for Free Electron Laser Science , 22761 Hamburg , Germany
| | - Inga von Ahnen
- Department of Physics , University of Hamburg and Max Planck Institute for the Structure and Dynamics of Matter, Center for Free Electron Laser Science , 22761 Hamburg , Germany
| | - Amy A Cordones
- Ultrafast X-ray Science Lab, Chemical Sciences Division , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
| | - Kiryong Hong
- Department of Chemistry and Chemistry Institute of Functional Materials , Pusan National University , Busan 46241 , South Korea
| | - Jae Hyuk Lee
- Ultrafast X-ray Science Lab, Chemical Sciences Division , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
| | - Rory Ma
- Department of Chemistry and Chemistry Institute of Functional Materials , Pusan National University , Busan 46241 , South Korea
| | - Katrin Adamczyk
- Department of Physics , University of Hamburg and Max Planck Institute for the Structure and Dynamics of Matter, Center for Free Electron Laser Science , 22761 Hamburg , Germany
| | - Tae Kyu Kim
- Department of Chemistry and Chemistry Institute of Functional Materials , Pusan National University , Busan 46241 , South Korea
| | - Robert W Schoenlein
- Ultrafast X-ray Science Lab, Chemical Sciences Division , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
| | - Oriol Vendrell
- Center for Free-Electron Laser Science , DESY and The Hamburg Centre for Ultrafast Imaging , 22607 Hamburg , Germany
| | - Nils Huse
- Department of Physics , University of Hamburg and Max Planck Institute for the Structure and Dynamics of Matter, Center for Free Electron Laser Science , 22761 Hamburg , Germany
| |
Collapse
|
8
|
Roy A, Seidel R, Kumar G, Bradforth SE. Exploring Redox Properties of Aromatic Amino Acids in Water: Contrasting Single Photon vs Resonant Multiphoton Ionization in Aqueous Solutions. J Phys Chem B 2018. [DOI: 10.1021/acs.jpcb.7b11762] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Anirban Roy
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482, United States
| | - Robert Seidel
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482, United States
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Straße 15, 12489 Berlin, Germany
| | - Gaurav Kumar
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482, United States
| | - Stephen E. Bradforth
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482, United States
| |
Collapse
|
9
|
Patankar S, Yang ST, Moody JD, Swadling GF, Erlandson AC, Bayramian AJ, Barker D, Datte P, Acree RL, Pepmeier B, Madden RE, Borden MR, Ross JS. Two-photon absorption measurements of deep UV transmissible materials at 213 nm. APPLIED OPTICS 2017; 56:8309-8312. [PMID: 29091606 DOI: 10.1364/ao.56.008309] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Accepted: 09/18/2017] [Indexed: 06/07/2023]
Abstract
We report on two-photon absorption measurements at 213 nm of deep UV transmissible media, including LiF, MgF2, CaF2, BaF2, sapphire (Al2O3), and high-purity grades of fused-silica (SiO2). A high-stability 24 ps Nd:YAG laser operating at the 5th harmonic (213 nm) was used to generate a high-intensity, long-Rayleigh-length Gaussian focus inside the samples. The measurements of the fluoride crystals and sapphire indicate two-photon absorption coefficients between 0.004 and 0.82 cm/GW. We find that different grades of fused silica performed near identically for two-photon absorption; however, there are differences in linear losses associated with purity. A low two-photon absorption cross section is measured for MgF2, making it an ideal material for the propagation of high-intensity deep UV lasers.
Collapse
|
10
|
Müller M, Klenke A, Gottschall T, Klas R, Rothhardt C, Demmler S, Rothhardt J, Limpert J, Tünnermann A. High-average-power femtosecond laser at 258 nm. OPTICS LETTERS 2017; 42:2826-2829. [PMID: 28708179 DOI: 10.1364/ol.42.002826] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Accepted: 06/22/2017] [Indexed: 06/07/2023]
Abstract
We present an ultrafast fiber laser system delivering 4.6 W average power at 258 nm based on two-stage fourth-harmonic generation in beta barium borate (BBO). The beam quality is close to being diffraction limited with an M2 value of 1.3×1.6. The pulse duration is 150 fs, which, potentially, is compressible down to 40 fs. A plain BBO and a sapphire-BBO compound are compared with respect to the achievable beam quality in the conversion process. This laser is applicable in scientific and industrial fields. Further scaling to higher average power is discussed.
Collapse
|
11
|
Ruth AA, Dixneuf S, Orphal J. Laser-induced plasmas in ambient air for incoherent broadband cavity-enhanced absorption spectroscopy. OPTICS EXPRESS 2015; 23:6092-6101. [PMID: 25836833 DOI: 10.1364/oe.23.006092] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The emission from a laser-induced plasma in ambient air, generated by a high power femtosecond laser, was utilized as pulsed incoherent broadband light source in the center of a quasi-confocal high finesse cavity. The time dependent spectra of the light leaking from the cavity was compared with those of the laser-induced plasma emission without the cavity. It was found that the light emission was sustained by the cavity despite the initially large optical losses of the laser-induced plasma in the cavity. The light sustained by the cavity was used to measure part of the S(1) ← S(0) absorption spectrum of gaseous azulene at its vapour pressure at room temperature in ambient air as well as the strongly forbidden γ-band in molecular oxygen: b(1)Σ(g)(+)(ν'=2)←X(3)Σ(g)(-)(ν''=0).
Collapse
|
12
|
Rakhman A, Wang Y, Garcia F, Long C, Huang C, Takeda Y, Liu Y. Multifunctional optical correlator for picosecond ultraviolet laser pulse measurement. APPLIED OPTICS 2014; 53:7603-7609. [PMID: 25402928 DOI: 10.1364/ao.53.007603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
A compact multifunctional optical correlator system for pulse width measurement of ultrashort ultraviolet (UV) pulses has been designed and experimentally demonstrated. Both autocorrelation and cross-correlation functions are measured using a single nonlinear crystal, and the switching between two measurements requires no adjustment of phase matching and detector. The system can measure UV pulse widths from sub-picoseconds to 100 ps, and it involves no auxiliary pulse in the measurement. The measurement results on a burst-mode picosecond UV laser show a high-quality performance on speed, accuracy, resolution, and dynamic range. The proposed correlator can be applied to measure any ultrashort UV pulses produced through sum-frequency generation or second-harmonic generation.
Collapse
|
13
|
|
14
|
Stark SP, Travers JC, Russell PSJ. Extreme supercontinuum generation to the deep UV. OPTICS LETTERS 2012; 37:770-772. [PMID: 22378388 DOI: 10.1364/ol.37.000770] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We report the formation of an ultrabroad supercontinuum down to 280 nm in the deep UV by pumping sharply tapered (5-30 mm taper lengths) solid-core photonic crystal fibers with 130 fs, 2 nJ pulses at 800 nm. The taper moves the point of soliton fission to a position where the core is narrower, a process that requires normal dispersion at the input face of the fiber. We find that the generation of deep-UV radiation is limited by strong two-photon absorption in the silica.
Collapse
Affiliation(s)
- S P Stark
- Max Planck Institute for the Science of Light, Günther-Scharowsky-Strasse 1, 91058 Erlangen, Germany
| | | | | |
Collapse
|
15
|
Ren M, Jia B, Ou JY, Plum E, Zhang J, MacDonald KF, Nikolaenko AE, Xu J, Gu M, Zheludev NI. Nanostructured plasmonic medium for terahertz bandwidth all-optical switching. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2011; 23:5540-5544. [PMID: 22021040 DOI: 10.1002/adma.201103162] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2011] [Indexed: 05/27/2023]
Abstract
Periodic nanostructuring can enhance the optical nonlinearity of plasmonic metals by several orders of magnitude. By patterning a gold film, the largest sub-100 femtosecond nonlinearity is achieved, which is suitable for terahertz rate all-optical data processing as well as ultrafast optical limiters and saturable absorbers.
Collapse
Affiliation(s)
- Mengxin Ren
- Optoelectronics Research Centre, University of Southampton, UK
| | | | | | | | | | | | | | | | | | | |
Collapse
|
16
|
Yu F, Kachanov AA, Koulikov S, Wainright A, Zare RN. Ultraviolet thermal lensing detection of amino acids. J Chromatogr A 2009; 1216:3423-30. [DOI: 10.1016/j.chroma.2008.05.096] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2008] [Revised: 05/25/2008] [Accepted: 05/30/2008] [Indexed: 11/16/2022]
|
17
|
Brambilla G, Fotiadi AA, Slattery SA, Nikogosyan DN. Two-photon photochemical long-period grating fabrication in pure-fused-silica photonic crystal fiber. OPTICS LETTERS 2006; 31:2675-7. [PMID: 16936854 DOI: 10.1364/ol.31.002675] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
We report what is to our knowledge the first photochemical fabrication of a long-period grating in a pure-fused-silica photonic crystal fiber. The inscription technique is based on a two-photon absorption mechanism and does not require a specially designed photonic crystal fiber with a photosensitive Ge-doped core. The characteristic fluence value for the inscription is an order of magnitude less than that for a standard telecom fiber irradiated under similar conditions with the same grating parameters.
Collapse
|
18
|
Abbas Ghaleb K, Georges J. Limitations arising from two-photon absorption of solvent in pulsed-laser thermal lens detection: determination of the two-photon absorption coefficient of ethanol at 266 nm. APPLIED SPECTROSCOPY 2006; 60:86-8. [PMID: 16454917 DOI: 10.1366/000370206775382802] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Two-photon absorption of the solvent under pulsed-laser excitation at 266 nm produces a high background thermal lens signal interfering with the analyte signal. Discrimination of both solvent and analyte signals along with calibration of the photothermal response has allowed the determination of the two-photon absorption coefficient of ethanol. The obtained value, 3.0x10(-10) cm W-1, is close to the literature values obtained from transmittance measurements using picosecond or femtosecond laser pulses.
Collapse
Affiliation(s)
- Khalil Abbas Ghaleb
- Laboratoire des Sciences Analytiques, UMR 5180, Bât.-308D, Domaine Scientifique de la Doua, Université Claude Bernard-Lyon 1, 69622 Villeurbanne Cedex, France
| | | |
Collapse
|
19
|
Dubov M, Bennion I, Slattery SA, Nikogosyan DN. Strong long-period fiber gratings recorded at 352 nm. OPTICS LETTERS 2005; 30:2533-5. [PMID: 16208890 DOI: 10.1364/ol.30.002533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
We describe long-period grating inscription in hydrogenated telecom fibers by use of high-intensity femtosecond 352 nm laser pulses. We show that this technique allows us to fabricate high-quality 30 dB gratings of 300 microm period and 2 cm length by use of a three-photon absorption mechanism.
Collapse
Affiliation(s)
- Mykhaylo Dubov
- Photonics Research Group, Electronic Engineering, Aston University, Birmingham B4 7ET, UK
| | | | | | | |
Collapse
|
20
|
Beyer O, Maxein D, Buse K, Sturman B, Hsieh HT, Psaltis D. Femtosecond time-resolved absorption processes in lithium niobate crystals. OPTICS LETTERS 2005; 30:1366-8. [PMID: 15981535 DOI: 10.1364/ol.30.001366] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Femtosecond pump pulses are strongly attenuated in lithium niobate owing to two-photon absorption; the relevant nonlinear coefficient beta(p) ranges from approximately 3.5 cm/GW for lambda(p) = 388 nm to approximately 0.1 cm/GW for 514 nm. In collinear pump-probe experiments the probe transmission at the double pump wavelength 2lambda(p) = 776 nm is controlled by two different processes: A direct absorption process involving pump and probe photons (beta (r) = 0.9 cm/GW) leads to a pronounced short-duration transmission dip, whereas the probe absorption by pump-excited charge carriers results in a long-duration plateau. Coherent pump-probe interactions are of no importance. Hot-carrier relaxation occurs on the time scale of < or approximately equal to 0.1 ps.
Collapse
Affiliation(s)
- O Beyer
- Physikalisches Institut, University of Bonn, Wegelerstrasse 8, D-53115 Bonn, Germany.
| | | | | | | | | | | |
Collapse
|
21
|
Beyer O, Maxein D, Buse K, Sturman B, Hsieh HT, Psaltis D. Investigation of nonlinear absorption processes with femtosecond light pulses in lithium niobate crystals. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2005; 71:056603. [PMID: 16089664 DOI: 10.1103/physreve.71.056603] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2004] [Indexed: 05/03/2023]
Abstract
The propagation of high-power femtosecond light pulses in lithium niobate crystals (LiNb O3 ) is investigated experimentally and theoretically in collinear pump-probe transmission experiments. It is found within a wide intensity range that a strong decrease of the pump transmission coefficient at wavelength 388 nm fully complies with the model of two-photon absorption; the corresponding nonlinear absorption coefficient is beta(p) approximately = 3.5 cm/GW. Furthermore, strong pump pulses induce a considerable absorption for the probe at 776 nm. The dependence of the probe transmission coefficient on the time delay Delta t between probe and pump pulses is characterized by a narrow dip (at Delta t approximately = 0) and a long (on the picosecond time scale) lasting plateau. The dip is due to direct two-photon transitions involving pump and probe photons; the corresponding nonlinear absorption coefficient is beta(r) approximately = 0.9 cm/GW. The plateau absorption is caused by the presence of pump-excited charge carriers; the effective absorption cross section at 776 nm is sigma(r) approximately = 8 x 10(-18) cm(2). The above nonlinear absorption parameters are not strongly polarization sensitive. No specific manifestations of the relaxation of hot carriers are found for a pulse duration of approximately = 0.24 ps.
Collapse
Affiliation(s)
- O Beyer
- Institute of Physics, University of Bonn, Wegelerstr. 8, D-53115 Bonn, Germany.
| | | | | | | | | | | |
Collapse
|
22
|
Dragomir A, Nikogosyan DN, Zagorulko KA, Kryukov PG, Dianov EM. Inscription of fiber Bragg gratings by ultraviolet femtosecond radiation. OPTICS LETTERS 2003; 28:2171-2173. [PMID: 14649931 DOI: 10.1364/ol.28.002171] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
We report on what is to our knowledge the first fabrication of fiber Bragg gratings by UV femtosecond radiation. The Bragg gratings, with photoinduced refractive-index modulation up to 1.92 x 10(-3) in H2-loaded SMF-28 and up to 1.05 x 10(-3) in Nufern GF1 fibers, were written by high-intensity (31-77-GW/cm2) femtosecond pulses at 264 nm. The dependence of the refractive-index modulation on intensity at equal fluences points to a two-photon absorption mechanism for grating inscription.
Collapse
Affiliation(s)
- Adrian Dragomir
- Department of Physics, National University of Ireland, University College Cork, Cork, Ireland
| | | | | | | | | |
Collapse
|
23
|
Aramendía PF, Viappiani C, Wilkinson F. Editorial: Professor Silvia Braslavsky. Photochem Photobiol Sci 2003; 2:vii-viii. [PMID: 12911217 DOI: 10.1039/b305468c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|