1
|
Xue J, Zhang Z, Wang Y, Shang B, Guo J, Tao S, Zhang N, Guo L, Qi P, Lin L, Liu W. Coupled air lasing gain and Mie scattering loss: an aerosol effect in filament-induced plasma spectroscopy. OPTICS LETTERS 2024; 49:550-553. [PMID: 38300056 DOI: 10.1364/ol.506003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Accepted: 11/21/2023] [Indexed: 02/02/2024]
Abstract
Femtosecond laser filament-induced plasma spectroscopy (FIPS) demonstrates great potential in remote sensing for identifying atmospheric pollutant molecules. Due to the widespread aerosols in the atmosphere, remote detection based on FIPS would be affected by both the excitation and the propagation of fingerprint fluorescence, which still remain elusive. Here the physical model of filament-induced aerosol fluorescence is established to reveal the combined effect of Mie scattering and amplification spontaneous emission, which is subsequently proven by experimental results, the dependence of the backward fluorescence on the interaction length between filaments and aerosols. These findings provide an insight into the complicated aerosol effect in the overall physical process of FIPS including propagation, excitation, and emission, paving the way to its practical application in atmospheric remote sensing.
Collapse
|
2
|
Du W, Tang P, Yang B, Yang L, Li X, Duan M, Gou S, Ma Q. Metal-Free Hybrid Energetic Composites Based on Donor-Acceptor π-Conjugated Organic Energetic Catalysts with Enlightening the Laser Ignition Performance of Multi-Scale Ammonium Perchlorate. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023; 19:e2303678. [PMID: 37475508 DOI: 10.1002/smll.202303678] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 07/01/2023] [Indexed: 07/22/2023]
Abstract
Photosensitive materials, such as energetic complexes, usually have high sensitivity and cause heavy-metal pollution, whereas others, like carbon black and dye, do not contain energy, which affects energy output and mechanical properties. In this work, donor-acceptor π-conjugated energetic catalysts, denoted as D-n, are designed and synthesized. Nonmetallic hybrid energetic composites are prepared by assembling the as-synthesized catalysts into multiscale ammonium perchlorate (AP). Composites containing catalysts and APs can be successfully ignited without the involvement of metals. The new ignition mechanism is further analyzed using experimental and theoretical analyses such as UV-vis-near-infrared (NIR) spectra, electron-spin resonance spectroscopy, and energy-gap analysis. The shortest ignition delay time is 56 ms under the experimental condition of a NIR wavelength of 1064 nm and a laser power of 10 W. At the voltage of 1 kV and the electric field of 500 V mm-1 , the laser-ignition delay time of D-2/AP hybrid composite decreases from 56 to 35 ms because D-2 also exhibits organic semiconductor-like properties. D-2/AP and D-12/AP can also be used to successfully laser ignite other common energetic materials. This study can guide the development of advanced metal-free laser-ignitable energetic composites to address challenges in the field of aerospace engineering.
Collapse
Affiliation(s)
- Wei Du
- Institute of Chemical Materials, China Academy of Engineering Physics, Mianyang, 621900, China
- College of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu, 610500, China
| | - Pengfei Tang
- Institute of Chemical Materials, China Academy of Engineering Physics, Mianyang, 621900, China
| | - Bo Yang
- Institute of Chemical Materials, China Academy of Engineering Physics, Mianyang, 621900, China
| | - Lei Yang
- Institute of Chemical Materials, China Academy of Engineering Physics, Mianyang, 621900, China
| | - Xiaodong Li
- Institute of Chemical Materials, China Academy of Engineering Physics, Mianyang, 621900, China
| | - Ming Duan
- College of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu, 610500, China
| | - Shaohua Gou
- College of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu, 610500, China
| | - Qing Ma
- Institute of Chemical Materials, China Academy of Engineering Physics, Mianyang, 621900, China
| |
Collapse
|
3
|
Li D, Liang W, Li D, Ji L, Yan B, Chang J, Xi T, Zhang L, Cai Y, Hao Z. Distinguishing the nonlinear propagation regimes of vortex femtosecond pulses in fused silica by evaluating the broadened spectrum. OPTICS EXPRESS 2023; 31:32752-32760. [PMID: 37859070 DOI: 10.1364/oe.497418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Accepted: 09/07/2023] [Indexed: 10/21/2023]
Abstract
The nonlinear propagation dynamics of vortex femtosecond laser pulses in optical media is a topic with significant importance in various fields, such as nonlinear optics, micromachining, light bullet generation, vortex air lasing, air waveguide and supercontinuum generation. However, how to distinguish the various regimes of nonlinear propagation of vortex femtosecond pulses remains challenging. This study presents a simple method for distinguishing the regimes of nonlinear propagation of femtosecond pulses in fused silica by evaluating the broadening of the laser spectrum as the input pulse power gradually increases. The linear, self-focusing and mature filamentation regimes for Gaussian and vortex femtosecond pulses in fused silica are distinguished. The critical powers for self-focusing and mature filamentation of both types of laser pulses are obtained. Our work provides a rapid and convenient method for distinguishing different regimes of nonlinear propagation and determining the critical powers for self-focusing and mature filamentation of Gaussian and structured laser pulses in optical media.
Collapse
|
4
|
Zhang W, Chen J, Wang S, Li H, Zang H, Xu H. Energy deposition in a telescopic laser filament for the control of fuel ignition. OPTICS EXPRESS 2023; 31:33132-33140. [PMID: 37859100 DOI: 10.1364/oe.500042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Accepted: 09/05/2023] [Indexed: 10/21/2023]
Abstract
The efficiency of energy coupled to plasma during femtosecond (fs) laser filamentation plays a decisive role in a variety of filament applications such as remote fabrication and spectroscopy. However, the energy deposition characterization in the fs laser filament formed by a telescope, which provides an efficient way to extend the filament distance, has not yet been revealed. In the present study, we show that when the distance between the two lenses in a telescope changes, i.e., the effective focal length changes, there exists an optimal plateau energy deposition region in which the energy deposited into the filament per unit length called the average lineic energy deposition (ALED) remains at high levels, exhibiting a remarkable difference from the monotonic change in a single-lens focusing system. As a proof of principle, we examined the influence of the energy deposition on the ignition of a lean methane/air mixture, and found that the use of the telescope can efficiently extend the ignition distance when compared with a single-lens focusing system under the same incident laser energy condition. Our results may help understand the energy deposition behaviors in a variety of telescopic filaments and provide more options to manipulating laser ignition at a desired distance.
Collapse
|
5
|
Cao J, Fu Y, Wang S, Chen J, Cong X, Li H, Xu H. Transition from triggered super-radiance to seed amplification in N 2 + lasing. OPTICS LETTERS 2023; 48:526-529. [PMID: 36723522 DOI: 10.1364/ol.478967] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Accepted: 12/19/2022] [Indexed: 06/18/2023]
Abstract
Air lasing induced by laser filamentation opens a new route for research on atmospheric molecular physics and remote sensing. The generation of air lasing is composed of two processes, i.e., building up optical gain of air molecules in femtosecond time scale and emitting coherent radiation in picosecond time scale. Here, we focus on the emission mechanisms of N2 + air lasing and reveal, by examining the intensities and temporal profiles of N2 + lasing at 391 nm generated respectively in a time-varying polarization-modulated and a linearly polarized pump laser field under different nitrogen gas pressures, that the N2 + lasing can emit through either triggered super-radiance or seed amplification. We find that the two pressure-sensitive factors, i.e., the dipole dephasing time T2 and the population inversion density n, determine which of these two mechanisms dominates the N2 + lasing emission process, enabling manipulation of the transition from triggered super-radiance to seed amplification or vice versa. Our findings clarify the emission mechanism of N2 + lasing under different pressures and provide a deeper understanding of N2 + air lasing not only in the establishment of optical gain but also in the lasing emission process.
Collapse
|
6
|
Yao D, Hu Z, Zheng R, Li J, Wang L, Yang X, Lü W, Xu H. Black TiO 2-Based Dual Photoanodes Boost the Efficiency of Quantum Dot-Sensitized Solar Cells to 11.7. NANOMATERIALS (BASEL, SWITZERLAND) 2022; 12:4294. [PMID: 36500917 PMCID: PMC9741270 DOI: 10.3390/nano12234294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/15/2022] [Revised: 11/28/2022] [Accepted: 11/29/2022] [Indexed: 06/17/2023]
Abstract
Quantum dot-sensitized solar cells (QDSSC) have been regarded as one of the most promising candidates for effective utilization of solar energy, but its power conversion efficiency (PCE) is still far from meeting expectations. One of the most important bottlenecks is the limited collection efficiency of photogenerated electrons in the photoanodes. Herein, we design QDSSCs with a dual-photoanode architecture, and assemble the dual photoanodes with black TiO2 nanoparticles (NPs), which were processed by a femtosecond laser in the filamentation regime, and common CdS/CdSe QD sensitizers. A maximum PCE of 11.7% with a short circuit current density of 50.3 mA/cm2 is unambiguously achieved. We reveal both experimentally and theoretically that the enhanced PCE is mainly attributed to the improved light harvesting of black TiO2 due to the black TiO2 shells formed on white TiO2 NPs.
Collapse
Affiliation(s)
- Danwen Yao
- State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012, China
| | - Zhenyu Hu
- State Key Laboratory of Advanced Structural Materials, Ministry of Education, Changchun University of Technology, Changchun 130012, China
| | - Ruifeng Zheng
- State Key Laboratory of Advanced Structural Materials, Ministry of Education, Changchun University of Technology, Changchun 130012, China
| | - Jialun Li
- State Key Laboratory of Advanced Structural Materials, Ministry of Education, Changchun University of Technology, Changchun 130012, China
| | - Liying Wang
- State Key Laboratory of Advanced Structural Materials, Ministry of Education, Changchun University of Technology, Changchun 130012, China
| | - Xijia Yang
- State Key Laboratory of Advanced Structural Materials, Ministry of Education, Changchun University of Technology, Changchun 130012, China
| | - Wei Lü
- State Key Laboratory of Advanced Structural Materials, Ministry of Education, Changchun University of Technology, Changchun 130012, China
| | - Huailiang Xu
- State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012, China
- State Key Laboratory of Precision Spectroscopy and Chongqing Institute, East China Normal University, Shanghai 200062, China
| |
Collapse
|
7
|
Chen S, Cong X, Chen J, Zang H, Li H, Xu H. Sensing Trace-Level Metal Elements in Water Using Chirped Femtosecond Laser Pulses in the Filamentation Regime. SENSORS (BASEL, SWITZERLAND) 2022; 22:8775. [PMID: 36433371 PMCID: PMC9694792 DOI: 10.3390/s22228775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Revised: 10/31/2022] [Accepted: 11/11/2022] [Indexed: 06/16/2023]
Abstract
Femtosecond filament-induced breakdown spectroscopy (FIBS) is an efficient approach in remote and in situ detection of a variety of trace elements, but it was recently discovered that the FIBS of water is strongly dependent on the large-bandgap semiconductor property of water, making the FIBS signals sensitive to laser ionization mechanisms. Here, we show that the sensitivity of the FIBS technique in monitoring metal elements in water can be efficiently improved by using chirped femtosecond laser pulses, but an asymmetric enhancement of the FIBS intensity is observed for the negatively and positively chirped pulses. We attribute the asymmetric enhancement to their different ionization rates of water, in which the energy of the photons participating in the ionization process in the front part of the negatively chirped pulse is higher than that in the positively chirped pulse. By optimizing the pulse chirp, we show that the limit of detection of the FIBS technique for metal elements in water, e.g., aluminum, can reach to the sub-ppm level, which is about one order of magnitude better than that by the transform-limited pulse. We further examine the FIBS spectra of several representative water samples including commercial mineral water, tap water, and lake water taken from two different environmental zones, i.e., a national park and a downtown business district (Changchun, China), from which remarkably different concentrations of Ca, Na, and K elements of these samples are obtained. Our results provide a possibility of using FIBS for direct and fast metal elemental analysis of water in different field environments.
Collapse
Affiliation(s)
- Shanming Chen
- State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012, China
| | - Xun Cong
- State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012, China
| | - Junyan Chen
- State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012, China
| | - Hongwei Zang
- State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012, China
| | - Helong Li
- State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012, China
- Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012, China
| | - Huailiang Xu
- State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012, China
- State Key Laboratory of Precision Spectroscopy & Chongqing Institute, East China Normal University, Shanghai 200062, China
| |
Collapse
|
8
|
Qi P, Qian W, Guo L, Xue J, Zhang N, Wang Y, Zhang Z, Zhang Z, Lin L, Sun C, Zhu L, Liu W. Sensing with Femtosecond Laser Filamentation. SENSORS (BASEL, SWITZERLAND) 2022; 22:s22187076. [PMID: 36146424 PMCID: PMC9504994 DOI: 10.3390/s22187076] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Revised: 08/08/2022] [Accepted: 08/09/2022] [Indexed: 05/25/2023]
Abstract
Femtosecond laser filamentation is a unique nonlinear optical phenomenon when high-power ultrafast laser propagation in all transparent optical media. During filamentation in the atmosphere, the ultrastrong field of 1013-1014 W/cm2 with a large distance ranging from meter to kilometers can effectively ionize, break, and excite the molecules and fragments, resulting in characteristic fingerprint emissions, which provide a great opportunity for investigating strong-field molecules interaction in complicated environments, especially remote sensing. Additionally, the ultrastrong intensity inside the filament can damage almost all the detectors and ignite various intricate higher order nonlinear optical effects. These extreme physical conditions and complicated phenomena make the sensing and controlling of filamentation challenging. This paper mainly focuses on recent research advances in sensing with femtosecond laser filamentation, including fundamental physics, sensing and manipulating methods, typical filament-based sensing techniques and application scenarios, opportunities, and challenges toward the filament-based remote sensing under different complicated conditions.
Collapse
Affiliation(s)
- Pengfei Qi
- Institute of Modern Optics, Eye Institute, Nankai University, Tianjin 300350, China
- Tianjin Key Laboratory of Micro-Scale Optical Information Science and Technology, Tianjin 300350, China
| | - Wenqi Qian
- Institute of Modern Optics, Eye Institute, Nankai University, Tianjin 300350, China
- Tianjin Key Laboratory of Micro-Scale Optical Information Science and Technology, Tianjin 300350, China
| | - Lanjun Guo
- Institute of Modern Optics, Eye Institute, Nankai University, Tianjin 300350, China
- Tianjin Key Laboratory of Micro-Scale Optical Information Science and Technology, Tianjin 300350, China
| | - Jiayun Xue
- Institute of Modern Optics, Eye Institute, Nankai University, Tianjin 300350, China
- Tianjin Key Laboratory of Micro-Scale Optical Information Science and Technology, Tianjin 300350, China
| | - Nan Zhang
- Institute of Modern Optics, Eye Institute, Nankai University, Tianjin 300350, China
- Tianjin Key Laboratory of Micro-Scale Optical Information Science and Technology, Tianjin 300350, China
| | - Yuezheng Wang
- Institute of Modern Optics, Eye Institute, Nankai University, Tianjin 300350, China
- Tianjin Key Laboratory of Micro-Scale Optical Information Science and Technology, Tianjin 300350, China
| | - Zhi Zhang
- Institute of Modern Optics, Eye Institute, Nankai University, Tianjin 300350, China
- Tianjin Key Laboratory of Optoelectronic Sensor and Sensing Network Technology, Tianjin 300350, China
| | - Zeliang Zhang
- Institute of Modern Optics, Eye Institute, Nankai University, Tianjin 300350, China
- Tianjin Key Laboratory of Micro-Scale Optical Information Science and Technology, Tianjin 300350, China
| | - Lie Lin
- Institute of Modern Optics, Eye Institute, Nankai University, Tianjin 300350, China
- Tianjin Key Laboratory of Optoelectronic Sensor and Sensing Network Technology, Tianjin 300350, China
| | - Changlin Sun
- Institute of Modern Optics, Eye Institute, Nankai University, Tianjin 300350, China
- Tianjin Key Laboratory of Micro-Scale Optical Information Science and Technology, Tianjin 300350, China
- National Key Laboratory of Shock Wave and Detonation Physics, Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang 621900, China
| | - Liguo Zhu
- National Key Laboratory of Shock Wave and Detonation Physics, Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang 621900, China
| | - Weiwei Liu
- Institute of Modern Optics, Eye Institute, Nankai University, Tianjin 300350, China
- Tianjin Key Laboratory of Optoelectronic Sensor and Sensing Network Technology, Tianjin 300350, China
| |
Collapse
|
9
|
Zhang W, Liang T, Fu Y, Chen S, Zang H, Xu H. Probing ultrafast dynamics of soot in situ in a laminar diffusion flame using a femtosecond near-infrared laser pump and multi-color Rayleigh scattering probe spectroscopy. OPTICS EXPRESS 2022; 30:26182-26191. [PMID: 36236813 DOI: 10.1364/oe.461947] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Accepted: 06/26/2022] [Indexed: 06/16/2023]
Abstract
Soot nanoparticles result from incomplete combustion of fossil fuels, and have been exhibited, when released into the atmosphere, to be detrimental to air quality and human health. However, because of the inert and non-luminescent properties, probing the dynamics of soot in situ is still a challenge. Here we report a strong near-infrared laser pump and multi-color Rayleigh scattering probe approach to reveal soot dynamics in situ in a n-pentanol/air laminar diffusion flame at femtosecond time resolution. A size-dependent dynamical process of the pump-laser-induced soot swelling at femtosecond time scale and subsequent shrinking back to its original size at picosecond time scale is observed, in which both the swelling rise time and the shrinking decay time increase monotonically as the initial sizes of soot nanoparticles become larger. By characterizing the evolution time and intensity of the multi-color scattered probe light, the spatial distributions of different sizes of soot particles from the inception to the burnout regions of the flame are mapped, which provide useful information on exploring the formation and growth mechanisms of soot particles in flames.
Collapse
|
10
|
Xu X, Rudakov F, Weber PM. Chemical analysis from a distance: Spatially resolved, remote sensing using backward transient absorption. Chem Phys Lett 2022. [DOI: 10.1016/j.cplett.2022.139435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
11
|
Matsuda A, Tani K, Takeuchi Y, Hayakawa Y, Hishikawa A. Association Reaction of Gaseous C 2H 4 in Femtosecond Laser Filaments Studied by Time-of-Flight Mass Spectrometry. ACS OMEGA 2021; 6:29862-29868. [PMID: 34778659 PMCID: PMC8582076 DOI: 10.1021/acsomega.1c04354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 09/30/2021] [Indexed: 06/13/2023]
Abstract
Association reactions by femtosecond laser filamentation in gaseous C2H4 were studied by time-of-flight mass spectrometry of neutral reaction products. Direct sampling from the reaction cell to a mass spectrometer via a differential pumping stage allowed the identification of various hydrocarbon molecules C n H m with n = 3-7 and m = 4-7, which includes species not observed in the previous studies. It was found that products containing three and four carbon atoms dominate the mass spectrum with smaller yields for higher-mass species, suggesting that carbon chain growth proceeds through the reaction with C2H4 in the reaction cell. The product distribution showed a clear dependence on the laser pulse energy for filamentation.
Collapse
Affiliation(s)
- Akitaka Matsuda
- Department
of Chemistry, Graduate School of Science, Nagoya University, Furo-cho, Chikusa, Nagoya, Aichi 464-8602, Japan
| | - Kentaro Tani
- Department
of Chemistry, Graduate School of Science, Nagoya University, Furo-cho, Chikusa, Nagoya, Aichi 464-8602, Japan
| | - Yukari Takeuchi
- Department
of Chemistry, Graduate School of Science, Nagoya University, Furo-cho, Chikusa, Nagoya, Aichi 464-8602, Japan
| | - Yui Hayakawa
- Department
of Chemistry, Graduate School of Science, Nagoya University, Furo-cho, Chikusa, Nagoya, Aichi 464-8602, Japan
| | - Akiyoshi Hishikawa
- Department
of Chemistry, Graduate School of Science, Nagoya University, Furo-cho, Chikusa, Nagoya, Aichi 464-8602, Japan
- Research
Center for Materials Science, Nagoya University, Furo-cho, Chikusa, Nagoya, Aichi 464-8602, Japan
| |
Collapse
|
12
|
Skrodzki PJ, Burger M, Finney LA, Nawara R, Nees J, Jovanovic I. Millisecond-long suppression of spectroscopic optical signals using laser filamentation. OPTICS LETTERS 2021; 46:3777-3780. [PMID: 34329279 DOI: 10.1364/ol.430809] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Accepted: 07/06/2021] [Indexed: 06/13/2023]
Abstract
Ultrashort laser pulse filamentation in air can extend the delivery of focused laser energy to distances greatly exceeding the Rayleigh length. In this way, remote measurements can be conducted using many standard methods of analytical spectroscopy. The performance of spectroscopic techniques can be enhanced by temporal gating, which rejects the unwanted noise and background. In the present work, we investigate the thermal relaxation of air in the wake of single-filament plasmas using shadowgraphy. We demonstrate that the transient change in refractive index associated with relaxation of the gas can be used to reject both continuous and time-varying spectroscopic signals, including emission from laser-produced plasmas. This method can augment temporal gating of simple optical detectors.
Collapse
|