1
|
Gao J, Zhang X, Wang Y, Dong J, Lei M, Liu Y, Wu C, Gong Q, Jiang H. Controlling the Polarization of Nitrogen Ion Lasing. J Phys Chem Lett 2024; 15:3805-3811. [PMID: 38557052 DOI: 10.1021/acs.jpclett.4c00004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Air lasing provides a promising technique to remotely produce coherent radiation in the atmosphere and has attracted continuous attention. However, the polarization properties of N2+ lasing with seeding have not been understood since it was discovered 10 years ago, in which the polarization behaviors appear disordered and confusing. Here, we performed an experimental and theoretical investigation of the polarization properties of N2+ lasing and successfully revealed its underlying physical mechanism. We found that the optical gain is anisotropic, owing to the permanent alignment of N2+ induced by the preferential ionization of the pump light. As a result, the polarization of the N2+ lasing tends to align with that of the pump light after amplification, which becomes more pronounced as the amplification factor increases. Based on the permanent alignment of N2+, we built a theoretical model that analytically interpreted and numerically reproduced the experimental observations, which points out the key factors for controlling the polarization of N2+ lasing.
Collapse
Affiliation(s)
- Jingsong Gao
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
| | - Xiang Zhang
- Shanghai Key Lab of Modern Optical System, University of Shanghai for Science and Technology, Shanghai 200093, China
| | - Yang Wang
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
| | - Jiahao Dong
- Shanghai Key Lab of Modern Optical System, University of Shanghai for Science and Technology, Shanghai 200093, China
| | - Mingwei Lei
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
| | - Yi Liu
- Shanghai Key Lab of Modern Optical System, University of Shanghai for Science and Technology, Shanghai 200093, China
- CAS Center for Excellence in Ultra-intense Laser Science, Shanghai 201800, China
| | - Chengyin Wu
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
| | - Qihuang Gong
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
| | - Hongbing Jiang
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
| |
Collapse
|
2
|
Miao Z, Zheng W, Wang Y, Dai C, Li Z, Wu C. Optical amplification from high vibrational states of ionized nitrogen molecules generated by 800-nm femtosecond laser pulses. OPTICS EXPRESS 2021; 29:2279-2287. [PMID: 33726426 DOI: 10.1364/oe.414843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Accepted: 01/01/2021] [Indexed: 06/12/2023]
Abstract
We experimentally investigated the interaction between nitrogen molecules and intense femtosecond laser pulses. When irradiated by an 800-nm pump laser and a delayed 355-nm seed laser, the spectral lines around 353.3 nm and 353.8 nm are observed to be greatly amplified, no matter whether the pump laser is circularly or linearly polarized. The two spectral lines correspond to the transition of N2+ (B, ν' = 5 → X, ν = 4) and N2+ (B, ν' = 4 → X, ν = 3), respectively. In comparison with the spectral lines related with ground vibrational states of nitrogen molecular ion, the observed amplification exhibits different polarization dependence of the pump laser. This distinctive change can be explained by the population variation of high vibrational states caused by the pump laser with different polarizations.
Collapse
|
3
|
Li Z, Kuan YH, Mu X, Miao Z, Wu C, Liao WT. Ramsey interferometry through coherent A2Πu- X2Σg+- B2Σu+ coupling and population transfer in N2+ air laser. OPTICS LETTERS 2020; 45:6587-6590. [PMID: 33325846 DOI: 10.1364/ol.401800] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Accepted: 10/26/2020] [Indexed: 06/12/2023]
Abstract
Motivated by the hot debate on the mechanism of laser-like emission at 391 nm from N2 gas irradiated by a strong 800 nm pump laser and a weak 400 nm seed laser, we theoretically study the temporal profile, optical gain, and modulation of the 391 nm signal from N2+. Our calculation sheds light on the long standing controversy on whether population inversion is indispensable for optical gain and show the Ramsey fringes of the emission intensity at 391 nm formed by additionally injecting another 800 nm pump or 400 nm seed, which provides strong evidence for the coherence driven modulation of transition dipole moment and population transfer between the A2Πu(ν=2)-X2Σg+ states and the B2Σu+(ν=0)-X2Σg+ states. Our results show that the 391 nm optical gain is susceptible to the population inversion within N2+ states manipulated by the Ramsey technique and thus clearly reveal their symbiosis. This study reveals not only the physical picture of producing N2+ population inversion but also versatile control of the N2+ air laser.
Collapse
|
4
|
Li H, Pan S, Chen F, Sun F, Li Z, Xu H, Wu J. Optimization of N 2+ lasing by waveform-controlled polarization-skewed pulses. OPTICS LETTERS 2020; 45:6591-6594. [PMID: 33325847 DOI: 10.1364/ol.410153] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Accepted: 11/07/2020] [Indexed: 05/20/2023]
Abstract
Optical ionization of N2 and subsequent population redistribution among the ground and excited states of N2+ in an intense laser field are commonly accepted to be fundamentally responsible for the generation of N2+ lasing. By finely controlling this two-step process, the optimization of N2+ lasing is possibly achieved. Here, we design a waveform-controlled polarization-skewed (PS) pumping pulse, in which the leading and falling edges are orthogonally polarized, and their relative field strength and phase can be well controlled. We demonstrate that precise manipulation of the N2+ lasing at 391 nm and 428 nm emissions can be achieved by modulating both the relative phase and amplitudes of the two orthogonally polarized components of the pumping PS pulse. We find that the optimization of N2+ lasing depends not only on the competitive balance between the ionization and post-ionization coupling that varies in different pumping energies but also on the phase with the maximum intensity appearing at the phase of nπ. Orders of magnitude enhancement in the N2+ lasing intensity is observed as the phase changes from (n+1/2)π to nπ. The PS pulse with a controllable spatiotemporal waveform provides us a robust and straightforward tool to efficiently enhance the N2+ lasing emission.
Collapse
|
5
|
Li H, Lötstedt E, Li H, Zhou Y, Dong N, Deng L, Lu P, Ando T, Iwasaki A, Fu Y, Wang S, Wu J, Yamanouchi K, Xu H. Giant Enhancement of Air Lasing by Complete Population Inversion in N_{2}^{+}. PHYSICAL REVIEW LETTERS 2020; 125:053201. [PMID: 32794853 DOI: 10.1103/physrevlett.125.053201] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Accepted: 07/09/2020] [Indexed: 06/11/2023]
Abstract
A fine manipulation of population transfer among molecular quantum levels is a key technology for control of molecular processes. When a light field intensity is increased to the TW-PW cm^{-2} level, it becomes possible to transfer a population to specific excited levels through nonlinear light-molecule interaction, but it has been a challenge to control the extent of the population transfer. We deplete the population in the X^{2}Σ_{g}^{+}(v=0) state of N_{2}^{+} almost completely by focusing a dual-color (800 nm and 1.6 μm) intense femtosecond laser pulse in a nitrogen gas, and make the intensity of N_{2}^{+} lasing at 391 nm enhanced by 5-6 orders of magnitude. By solving a time-dependent Schrödinger equation describing the population transfer among the three lowest electronic states of N_{2}^{+}, we reveal that the X^{2}Σ_{g}^{+}(v=0) population is depleted by the vibrational Raman excitation followed by the electronic excitation A^{2}Π_{u}(v=2,3,4)←X^{2}Σ_{g}^{+}(v=1)←X^{2}Σ_{g}^{+}(v=0), resulting in the excessive population inversion between the B^{2}Σ_{u}^{+}(v=0) and X^{2}Σ_{g}^{+}(v=0) states. Our results offer a promising route to efficient population transfer among vibrational and electronic levels of molecules by a precisely designed intense laser field.
Collapse
Affiliation(s)
- Hanxiao Li
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, China
| | - Erik Lötstedt
- Department of Chemistry, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Helong Li
- State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012, China
| | - Yan Zhou
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, China
| | - Nana Dong
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, China
| | - Lunhua Deng
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, China
| | - Peifen Lu
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, China
| | - Toshiaki Ando
- Department of Chemistry, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Atsushi Iwasaki
- Department of Chemistry, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Yao Fu
- State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012, China
| | - Siqi Wang
- State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012, China
| | - Jian Wu
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
| | - Kaoru Yamanouchi
- Department of Chemistry, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Huailiang Xu
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, China
- State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012, China
- CAS Center for Excellence in Ultra-intense Laser Science, Shanghai 201800, China
| |
Collapse
|
6
|
Ando T, Lötstedt E, Iwasaki A, Li H, Fu Y, Wang S, Xu H, Yamanouchi K. Rotational, Vibrational, and Electronic Modulations in N_{2}^{+} Lasing at 391 nm: Evidence of Coherent B^{2}Σ_{u}^{+}-X^{2}Σ_{g}^{+}-A^{2}Π_{u} Coupling. PHYSICAL REVIEW LETTERS 2019; 123:203201. [PMID: 31809116 DOI: 10.1103/physrevlett.123.203201] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 08/23/2019] [Indexed: 06/10/2023]
Abstract
We investigate lasing of a N_{2} gas induced by intense few-cycle near-IR laser pulses. By the pump-probe measurements, we reveal that the intensity of the B^{2}Σ_{u}^{+}-X^{2}Σ_{g}^{+} lasing emission of N_{2}^{+} oscillates at high (0.3-0.5 PHz), medium (50-75 THz), and low (∼3 THz) frequencies, corresponding to the energy separations between the rovibrational levels of the A^{2}Π_{u} and X^{2}Σ_{g}^{+} states. By solving the time-dependent Schrödinger equation, we reproduce the oscillations in the three different frequency ranges and show that the coherent population transfer among the three electronic states of N_{2}^{+} creates the population inversion between the B^{2}Σ_{u}^{+} and X^{2}Σ_{g}^{+} states, resulting in the lasing at 391 nm.
Collapse
Affiliation(s)
- Toshiaki Ando
- Department of Chemistry, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Erik Lötstedt
- Department of Chemistry, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Atsushi Iwasaki
- Department of Chemistry, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Helong Li
- State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012, China
| | - Yao Fu
- State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012, China
| | - Siqi Wang
- State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, 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, East China Normal University, Shanghai 200062, China
| | - Kaoru Yamanouchi
- Department of Chemistry, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| |
Collapse
|
7
|
Zheng W, Miao Z, Zhang L, Wang Y, Dai C, Zhang A, Jiang H, Gong Q, Wu C. Enhanced Coherent Emission from Ionized Nitrogen Molecules by Femtosecond Laser Pulses. J Phys Chem Lett 2019; 10:6598-6603. [PMID: 31603688 DOI: 10.1021/acs.jpclett.9b02581] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The forward emission spectra were experimentally measured for ionized nitrogen molecules by an 800 nm pump laser and a delayed seed laser. It was found that emission lines around both 428 and 391 nm are greatly enhanced upon use of a 391 or 428 nm seed laser. The emission lines around 391 and 428 nm can be assigned to the rotational transitions of N2+ [B2Σu+(v' = 0) → X2Σg+(v = 0)] and N2+ [B2Σu+(v' = 0) → X2Σg+(v = 1)], respectively. They originate from seed-induced superfluorescence and resonant stimulated Raman scattering. The genetic algorithm was utilized to simulate the experimental observations and determine the relative population of B2Σu+(v' = 0), X2Σg+(v = 1), and X2Σg+(v = 0). The result verifies that vibrational population inversion is achieved between B2Σu+(v' = 0) and X2Σg+(v = 0) by the 800 nm pump laser. Our finding provides new insights into controlling the coherent emission of ionized nitrogen molecules, which has promising application in filamentation-based remote atmospheric sensing.
Collapse
Affiliation(s)
- Wei Zheng
- State Key Laboratory for Mesoscopic Physics, School of Physics , Peking University , Beijing 100871 , China
| | - Zhiming Miao
- State Key Laboratory for Mesoscopic Physics, School of Physics , Peking University , Beijing 100871 , China
| | - Linlin Zhang
- State Key Laboratory for Mesoscopic Physics, School of Physics , Peking University , Beijing 100871 , China
| | - Yang Wang
- State Key Laboratory for Mesoscopic Physics, School of Physics , Peking University , Beijing 100871 , China
| | - Chen Dai
- State Key Laboratory for Mesoscopic Physics, School of Physics , Peking University , Beijing 100871 , China
| | - An Zhang
- State Key Laboratory for Mesoscopic Physics, School of Physics , Peking University , Beijing 100871 , China
| | - Hongbing Jiang
- State Key Laboratory for Mesoscopic Physics, School of Physics , Peking University , Beijing 100871 , China
- Collaborative Innovation Center of Extreme Optics , Shanxi University , Taiyuan , Shanxi 030006 , China
| | - Qihuang Gong
- State Key Laboratory for Mesoscopic Physics, School of Physics , Peking University , Beijing 100871 , China
- Collaborative Innovation Center of Quantum Matter , Beijing 100871 , China
- Collaborative Innovation Center of Extreme Optics , Shanxi University , Taiyuan , Shanxi 030006 , China
- Frontiers Science Center for Nano-optoelectronics , Peking University , Beijing 100871 , China
| | - Chengyin Wu
- State Key Laboratory for Mesoscopic Physics, School of Physics , Peking University , Beijing 100871 , China
- Collaborative Innovation Center of Quantum Matter , Beijing 100871 , China
- Collaborative Innovation Center of Extreme Optics , Shanxi University , Taiyuan , Shanxi 030006 , China
- Frontiers Science Center for Nano-optoelectronics , Peking University , Beijing 100871 , China
| |
Collapse
|
8
|
Zhang A, Lei M, Gao J, Wu C, Gong Q, Jiang H. Subfemtosecond-resolved modulation of superfluorescence from ionized nitrogen molecules by 800-nm femtosecond laser pulses. OPTICS EXPRESS 2019; 27:14922-14930. [PMID: 31163933 DOI: 10.1364/oe.27.014922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Accepted: 05/02/2019] [Indexed: 06/09/2023]
Abstract
Superfluorescence emission around 391 nm is generated when nitrogen molecules are irradiated by a strong 800-nm pump laser and a delayed seed laser. The emission corresponds to the transition between N2+(B2Σu+,ν″=0) and N2+(X2Σg+,ν=0). When another weak 800-nm probe laser is injected and scanned after the pump laser, the superfluorescence intensity is observed to exhibit periodical modulation. The period is determined to be ~2.63 fs, corresponding to the transition frequency between N2+(A2Πu,ν'=2) and N2+(X2Σg+,ν=0). Based on theoretical derivation, these observations can be attributed to the laser-induced population transfer and polarization variation between the relevant electronic states of ionized nitrogen molecules.
Collapse
|
9
|
Britton M, Laferrière P, Ko DH, Li Z, Kong F, Brown G, Naumov A, Zhang C, Arissian L, Corkum PB. Testing the Role of Recollision in N_{2}^{+} Air Lasing. PHYSICAL REVIEW LETTERS 2018; 120:133208. [PMID: 29694197 DOI: 10.1103/physrevlett.120.133208] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Revised: 01/20/2018] [Indexed: 06/08/2023]
Abstract
It has been known for many years that during filamentation of femtosecond light pulses in air, gain is observed on the B to X transition in N_{2}^{+}. While the gain mechanism remains unclear, it has been proposed that recollision, a process that is fundamental to much of strong field science, is critical for establishing gain. We probe this hypothesis by directly comparing the influence of the ellipticity of the pump light on gain in air filaments. Then, we decouple filamentation from gain by measuring the gain in a thin gas jet that we also use for high harmonic generation. The latter allows us to compare the dependence of the gain on the ellipticity of the pump with the dependence of the high harmonic signal on the ellipticity of the fundamental. We find that gain and harmonic generation have very different behavior in both filaments and in the jet. In fact, in a jet we even measure gain with circular polarization. Thus, we establish that recollision does not play a significant role in creating the inversion.
Collapse
Affiliation(s)
| | | | - Dong Hyuk Ko
- University of Ottawa, Ottawa K1N 6N5, Ontario, Canada
| | - Zhengyan Li
- University of Ottawa, Ottawa K1N 6N5, Ontario, Canada
| | - Fanqi Kong
- University of Ottawa, Ottawa K1N 6N5, Ontario, Canada
| | - Graham Brown
- University of Ottawa, Ottawa K1N 6N5, Ontario, Canada
| | - Andrei Naumov
- National Research Council of Canada, Ottawa K1A 0R6, Ontario, Canada
| | - Chunmei Zhang
- University of Ottawa, Ottawa K1N 6N5, Ontario, Canada
| | - Ladan Arissian
- University of Ottawa, Ottawa K1N 6N5, Ontario, Canada
- National Research Council of Canada, Ottawa K1A 0R6, Ontario, Canada
- University of New Mexico, Albuquerque 87131, New Mexico, USA
| | - P B Corkum
- University of Ottawa, Ottawa K1N 6N5, Ontario, Canada
- National Research Council of Canada, Ottawa K1A 0R6, Ontario, Canada
| |
Collapse
|