[1] X.-C. Zhang, A. Shkurinov, Y. Zhang. Extreme terahertz science. Nat. Photonics, 11, 16-18(2017).

[2] K. Y. Kim, J. H. Glownia, A. J. Taylor, G. Rodriguez. Terahertz emission from ultrafast ionizing air in symmetry-broken laser fields. Opt. Express, 15, 4577-4584(2007).

[3] A. V. Balakin, A. V. Borodin, I. A. Kotelnikov, A. P. Shkurinov. Terahertz emission from a femtosecond laser focus in a two-color scheme. J. Opt. Soc. Am. B, 27, 16-26(2010).

[4] M. Li, W. Li, Y. Shi, P. Lu, H. Pan, H. Zeng. Verification of the physical mechanism of THz generation by dual-color ultrashort laser pulses. Appl. Phys. Lett., 101, 161104(2012).

[5] D. J. Cook, R. M. Hochstrasser. Intense terahertz pulses by four-wave rectification in air. Opt. Lett., 25, 1210-1212(2000).

[6] N. Bloembergen, Y. R. Shen. Optical nonlinearities in a plasma. Phys. Rev., 145, 390(1966).

[7] A. V. Borodin, N. A. Panov, O. G. Kosareva, V. A. Andreeva, M. N. Esaulkov, V. A. Makarov, A. P. Shkurinov, S. L. Chin, X.-C. Zhang. Transformation of terahertz spectra emitted from dual-frequency femtosecond pulse interaction in gases. Opt. Lett., 38, 1906-1908(2013).

[8] Q. Jin, Y. E, K. Williams, J. Dai, X.-C. Zhang. Observation of broadband terahertz wave generation from liquid water. Appl. Phys. Lett., 111, 071103(2017).

[9] Q. Jin, J. Dai, Y. E, X.-C. Zhang. Terahertz wave emission from a liquid water film under the excitation of asymmetric optical fields. Appl. Phys. Lett., 113, 261101(2018).

[10] T. Wang, P. Klarskov, P. U. Jepsen. Ultrabroadband THz time-domain spectroscopy of a free-flowing water film. IEEE Trans. Terahertz Sci. Technol., 4, 425-431(2014).

[11] A. V. Balakin, S. V. Garnov, V. A. Makarov, N. A. Kuzechkin, P. A. Obraztsov, P. M. Solyankin, A. P. Shkurinov, Y. Zhu. “Terhune-like” transformation of the terahertz polarization ellipse “mutually induced” by three-wave joint propagation in liquid. Opt. Lett., 43, 4406-4409(2018).

[12] I. Dey, K. Jana, V. Y. Fedorov, A. D. Koulouklidis, A. Mondal, M. Shaikh, D. Sarkar, A. D. Lad, S. Tzortzakis, A. Couairon, G. R. Kumar. Highly efficient broadband terahertz generation from ultrashort laser filamentation in liquids. Nat. Commun., 8, 1184(2017).

[13] Y. E, Q. Jin, A. Tcypkin, X.-C. Zhang. Terahertz wave generation from liquid water films via laser-induced breakdown. Appl. Phys. Lett., 113, 181103(2018).

[14] H. Kildal, S. R. J. Brueck. Orientational and electronic contributions to the third order susceptibilities of cryogenic liquids. J. Chem. Phys., 73, 4851-4958(1980).

[15] J. Samios, U. Mittag, T. Dorfmuller. The far infrared absorption spectrum of liquid nitrogen. Molecular Physics, 56, 541-556(1985).

[16] A. Siegman. Lasers(1986).

[17] K. Y. Kim, A. J. Taylor, J. H. Glownia, G. Rodriguez. Coherent control of terahertz supercontinuum generation in ultrafast laser-gas interactions. Nat. Photonics, 2, 605-609(2008).

[18] N. V. Vvedenskii, A. I. Korytin, V. A. Kostin, A. A. Murzanev, A. A. Silaev, A. N. Stepanov. Two-color laser-plasma generation of terahertz radiation using a frequency-tunable half harmonic of a femtosecond pulse. Phys. Rev. Lett., 112, 055004(2014).

[19] V. A. Kostin, I. D. Laryushin, A. A. Silaev, N. V. Vvedenskii. Ionization-induced multiwave mixing: terahertz generation with two-color laser pulses of various frequency ratios. Phys. Rev. Lett., 117, 035003(2016).

[20] W.-M. Wang, Z.-M. Sheng, H.-C. Wu, M. Chen, C. Li, J. Zhang, K. Mima. Strong terahertz pulse generation by chirped laser pulses in tenuous gases. Opt. Express, 16, 16999-17006(2008).

[21] C. F. Barnett, M. F. A. Harrison. Applied Atomic Collision Physics: Plasmas, 2(1984).

[22] A. V. Balakin, M. S. Dzhidzhoev, V. M. Gordienko, M. N. Esaulkov, I. A. Zhvaniya, K. A. Ivanov, I. A. Kotelnikov, N. A. Kuzechkin, I. A. Ozheredov, V. Y. Panchenko, A. B. Savel’ev, M. B. Smirnov, P. M. Solyankin, A. P. Shkurinov. Interaction of high-intensity femtosecond radiation with gas cluster beam: effect of pulse duration on joint terahertz and X-ray emission. IEEE Trans. Terahertz Sci. Technol., 7, 70-79(2017).

[23] K. Mori, M. Hashida, T. Nagashima, D. Li, K. Teramoto, Y. Nakamiya, S. Inoue, S. Sakabe. Directional linearly polarized terahertz emission from argon clusters irradiated by noncollinear double-pulse beams. Appl. Phys. Lett., 111, 241107(2017).

[24] A. Houard, Y. Liu, B. Prade, V. T. Tikhonchuk, A. Mysyrowicz. Strong enhancement of terahertz radiation from laser filaments in air by a static electric field. Phys. Rev. Lett., 100, 255006(2008).

[25] N. A. Panov, O. G. Kosareva, V. A. Andreeva, A. B. Savel’ev, D. S. Uryupina, R. V. Volkov, V. A. Makarov, A. P. Shkurinov. Angular distribution of the terahertz radiation intensity from the plasma channel of a femtosecond filament. JETP Lett., 93, 638-641(2011).

[26] W. Schottky. Diffusionstheorie der positiven säule. Phys. Zeits, 25, 635(1924).

[27] L. D. Landau, E. M. Lifshitz. Physical Kinetics: Course of Theoretical Physics, X(1984).

[28] R. W. Boyd. Nonlinear Optics(1992).

[29] W.-F. Sun, Y.-S. Zhou, X.-K. Wang, Y. Zhang. External electric field control of THz pulse generation in ambient air. Opt. Express, 16, 16573-16580(2008).