Lithuanian Journal of Physics article / Lietuvos fizikos žurnalo straipsnis

TERAHERTZ PHOTONICS OF MICROPLASMA AND BEYOND
Xi-Cheng Zhang^a,b and Fabrizio Buccheri^a
^aThe Institute of Optics, University of Rochester, Rochester, NY 14627, USA
^bThe Beijing Advanced Innovation Center for Imaging Technology, Capital Normal University, Beijing 100037, China
E-mail: xi-cheng.zhang@rochester.edu

Received 18 January 2018; accepted 22 March 2018

THz air photonics using laser-induced air plasma is one of the leading frontiers in the THz community. Ambient air, when excited with an intense femtosecond laser beam, exhibits the remarkable ability to generate and detect pulsed THz waves through a nonlinear optical process. Significant advances in the use of air plasma for emitting, controlling, enhancing and measuring broadband THz waves have opened up a range of research opportunities. However, one of the major challenges for the research community and in real world applications is that plasma formation requires the use of an intense laser (mJ pulse energy), but most femtosecond laser oscillators only have pulse energies in the range of pJ to tens of nJ. The investigation of THz photonics, specifically the exploration of laser-induced plasmas at the micro-nano scale and beyond, is a frontier. Microplasmas generated by tightly focused optical excitation beams with controlled polarization serve as a new THz source with its unique radiation pattern and easy operation. The laser energy threshold for THz wave generation, the power scaling and the generation efficiency from microplasmas are significantly different from those of elongated plasmas. Our estimation indicates that the micronano plasma approach could reduce the necessary optical pulse energy by five orders of magnitude, while still obtaining a comparable or better signal-to-noise ratio for THz time-domain spectroscopy. This would be made possible by the high electron density (10¹⁹ cm^–3 or more) achievable with a tight focus laser excitation, which correlates with the THz generation efficiency, and the use of laser oscillators with a much higher pulse repetition rate, as compared to the currently employed amplified laser systems (100 MHz vs 1 kHz). The THz micro-nano plasma is expected to lead to key technologies that will enable further interdisciplinary research and continued advancements of numerous THz wave sensing and spectroscopy developments. It serves as a vehicle for studying the extreme THz science.

Keywords: ultrafast optical phenomena, infrared, submillimetre wave, microwave and radiowave sources, ultrafast spectroscopy
PACS: 07.57.Hm, 78.47.J-

TERAHERCINĖ MIKROPLAZMOS FOTONIKA IR DAR DAUGIAU
Xi-Cheng Zhang^a,b, Fabrizio Buccheri^a

^aRočesterio universiteto Optikos institutas, Ročesteris, JAV
^bCapital Normal universitetas, Pekinas, Kinija

References / Nuorodos

[1] A. Couairon and A. Mysyrowicz, Femtosecond filamentation in transparent media, Phys. Rep. 441, 47–189 (2007),
https://doi.org/10.1016/j.physrep.2006.12.005
[2] N. Karpowicz, J. Dai, X. Lu, Y. Chen, M. Yamaguchi, H. Zhao, X.-C. Zhang, L. Zhang, C. Zhang, M. Price-Gallagher, C. Fletcher, O. Mamer, A. Lesimple, and K. Johnson, Coherent heterodyne time-domain spectrometry covering the entire "terahertz gap", Appl. Phys. Lett. 92, 011131 (2008),
https://doi.org/10.1063/1.2828709
[3] X. Xie, J. Dai, and X.-C. Zhang, Coherent control of THz wave generation in ambient air, Phys. Rev. Lett. 96, 075005 (2006),
https://doi.org/10.1103/PhysRevLett.96.075005
[4] J. Dai, X. Xie, and X.-C. Zhang, Detection of broadband terahertz waves with a laser-induced plasma in gases, Phys. Rev. Lett. 97, 103903 (2006),
https://doi.org/10.1103/PhysRevLett.97.103903
[5] D.J. Cook and R.M. Hochstrasser, Intense terahertz pulses by four-wave rectification in air, Opt. Lett. 25, 1210–1212 (2000),
https://doi.org/10.1364/OL.25.001210
[6] S. Tzortzakis, G. Méchain, G. Patalano, Y.-B. André, B. Prade, M. Franco, A. Mysyrowicz, J.-M. Munier, M. Gheudin, G. Beaudin, and P. Encrenaz, Coherent subterahertz radiation from femtosecond infrared filaments in air, Opt. Lett. 27, 1944–1946 (2002),
https://doi.org/10.1364/OL.27.001944
[7] M. Kress, T. Löffler, S. Eden, M. Thomson, and H.G. Roskos, Terahertz-pulse generation by photoionization of air with laser pulses composed of both fundamental and second-harmonic waves, Opt. Lett. 29, 1120–1122 (2004),
https://doi.org/10.1364/OL.29.001120
[8] T. Löffler, M. Kress, M. Thomson, and H.G. Roskos, Efficient terahertz pulse generation in laser-induced gas plasmas, Acta Phys. Pol. A 107, 99 (2005),
https://doi.org/10.12693/APhysPolA.107.99
[9] T. Bartel, P. Gaal, K. Reimann, M. Woerner, and T. Elsaesser, Generation of single-cycle THz transients with high electric-field amplitudes, Opt. Lett. 30, 2805–2807 (2005),
https://doi.org/10.1364/OL.30.002805
[10] A. Nahata and T.F. Heinz, Detection of freely propagating terahertz radiation by use of optical second-harmonic generation, Opt. Lett. 23, 67–69 (1998),
https://doi.org/10.1364/OL.23.000067
[11] D.J. Cook, J.X. Chen, E.A. Morlino, and R.M. Hochstrasser, Terahertz-field-induced second-harmonic generation measurements of liquid dynamics, Chem. Phys. Lett. 309, 221–228 (1999),
https://doi.org/10.1016/S0009-2614(99)00668-5
[12] R.W. Boyd, in: Nonlinear Optics, ed. S. Miyata (Academic Press, Boston, 1992),
https://www.elsevier.com/books/nonlinear-optics/miyata/978-0-444-89304-8
[13] H. Hamster, A. Sullivan, S. Gordon, W. White, and R.W. Falcone, Subpicosecond electromagnetic pulses from intense laser-plasma interaction, Phys. Rev. Lett. 71, 2725–2728 (1993),
https://doi.org/10.1103/PhysRevLett.71.2725
[14] C. D'Amico, A. Houard, M. Franco, B. Prade, and A. Mysyrowicz, Conical forward THz emission from femtosecond-laser-beam filamentation in air, Phys. Rev. Lett. 98, 235002 (2007),
https://doi.org/10.1103/PhysRevLett.98.235002
[15] H. Hamster, A. Sullivan, S. Gordon, and R.W. Falcone, Short-pulse terahertz radiation from high-intensity-laser-produced plasmas, Phys. Rev. E 49, 671–678 (1994),
https://doi.org/10.1103/PhysRevE.49.671
[16] M. Clerici, M. Peccianti, B. Schmidt, L. Caspani, M. Shalaby, M. Giguere, A. Lotti, A. Couairon, F. Legare, T. Ozaki, D. Faccio, and R. Morandotti, Wavelength scaling of terahertz generation by gas ionization, Phys. Rev. Lett. 110, 253901 (2013),
https://doi.org/10.1103/PhysRevLett.110.253901
[17] K.Y. Kim, J.H. Glownia, A.J. Taylor, and G. Rodriguez, Terahertz emission from ultrafast ionizing air in symmetry-broken laser fields, Opt. Express 15, 4577–4584 (2007),
https://doi.org/10.1364/OE.15.004577
[18] J. Dai, N. Karpowicz, and X.-C. Zhang, Coherent polarization control of terahertz waves generated from two-colour laser-induced gas plasma, Phys. Rev. Lett. 103, 023001 (2009),
https://doi.org/10.1103/PhysRevLett.103.023001
[19] H. Wen and A.M. Lindenberg, Coherent terahertz polarization control through manipulation of electron trajectories, Phys. Rev. Lett. 103, 023904 (2009),
https://doi.org/10.1103/PhysRevLett.103.023902
[20] X. Suan and X.-C. Zhang, Terahertz radiation in alkali vapour plasmas, Appl. Phys. Lett. 104, 191106 (2014),
https://doi.org/10.1063/1.4876602
[21] L. Neukirch, J. Gieseler, R. Quidant, L. Novotny, and A. Vamivakas, Observation of nitrogen vacancy photoluminescence from an optically levitated nanodiamond, Opt. Lett. 38, 2976–2979 (2013),
https://doi.org/10.1364/OL.38.002976
[22] J. Liu and X.-C. Zhang, Terahertz-radiation-enhanced emission of fluorescence from gas plasma, Phys. Rev. Lett. 103, 235002 (2009),
https://doi.org/10.1103/PhysRevLett.103.235002
[23] J. Liu, J. Dai, S.L. Chin, and X.-C. Zhang, Broadband terahertz wave remote sensing using coherent manipulation of fluorescence from asymmetrically ionized gases, Nat. Photonics 4, 627–631 (2010),
https://doi.org/10.1038/nphoton.2010.165
[24] A. Ashkin, J. Dziedzic, J. Bjorkholm, and S. Chu, Observation of a single-beam gradient optical trap for dielectric particles, Opt. Lett. 11, 288–290 (1986),
https://doi.org/10.1364/OL.11.000288
[25] A. Ashkin and J. Dziedzic, Optical levitation by radiation pressure, Appl. Phys. Lett. 19, 283–285 (1971),
https://doi.org/10.1063/1.1653919
[26] G. Swartzlander, T. Peterson, A. Artusio-Glimpse, and A. Raisanen, Stable optical lift, Nat. Photonics 5, 48–51 (2011),
https://doi.org/10.1038/nphoton.2010.266
[27] J. Liesener, M. Reicherter, T. Haist, and H. Tiziani, Multi-functional optical tweezers using computer-generated holograms, Opt. Commun. 185, 77–82 (2000),
https://doi.org/10.1016/S0030-4018(00)00990-1
[28] A. Adam, Review of near-field terahertz measurement methods and their applications, J. Infrared Millim. Terahertz Waves 32, 976–1019 (2011),
https://doi.org/10.1007/s10762-011-9809-2