General Information Name Gender Birth Citizenship Major Email Address Qing Liao Male 27/02/1983, China Chinese Physical Electronics liaoqing@phys.ksu.edu Department of Physics, Kansas State University, 116 Cardwell Hall Manhattan, KS 66506, USA Education 09/2005-06/2009 Ph.D., Physical Electronics, School of Optoelectronic Science and Engineering, Huazhong University of Science and Technology, Wuhan, P. R. China Advisor: Peixiang Lu Dissertation Title: Measurement of Phase of Ultrashort Pulses and Electron Correlation in Nonsequential Double ionization 09/2001-06/2005 B.Sc., Applied Physics, Department of Physics, Huazhong University of Science and Technology, Wuhan, P. R. China Work and Professional Experience 04/2012-03/2015 Postdoctoral Fellow, Department of Physics, Kansas State University, USA 08/2009-12/2011 Postdoctoral Fellow, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, China (1) Above Threshold Ionization. By numerically solving the time-dependent Schrodinger equation (TDSE), I studied the carrier-envelope phase (CEP) dependence of high-order 1
above-threshold ionization of HeH 2+ molecules and the interference of returning photoelectron wave packets associated with the long and the short quantum paths. The much larger left-right asymmetry of photoelectron yield of HeH 2+ than that of atoms and the extreme phase sensitivity of large-scale interference fringes were proposed as tools to precisely measure CEP. (2) Nonsequential Double Ionization. Extending TDSE to a correlated two-electron model, I studied double ionization of HeH + molecules and found that both nonsequential double ionization (NSDI) and sequential double ionization (SDI) mechanisms induced events exhibit asymmetric distribution in the two-electron momentum spectra, and they are separated in the two-electron momentum distributions, due to the asymmetric charge configuration of HeH +. The manipulating of the two-electron emission direction and yield was demonstrated in NSDI of HeH + using classical ensemble model. I also explored the mechanism of NSDI at NIR wavelengths and low laser intensities: multiphoton double ionization from doubly excited states induced by recollision, which reasonably explains the recent experimental results. In addition, I found multiphoton Rabi oscillation of double-electron in He atoms at UV wavelengths. The corresponding Rabi frequency and period are identified by the two-electron energy spectra and by time-resolved double ionization yield respectively. Rabi oscillation of two correlated electrons are expected to be used in quantum coherent control. (3) Attosecond Streaking Photoemission Time Delay. Recent two years, I have been working in the group of Prof. Uwe Thumm on quantum-mechanical simulations of attosecond streaking photoemission from condensed matter systems such as metal and metal-metal systems. We have established a quantum-mechanical model, based on strong-field approximation, which quantitatively reproduces measured relative streaking time delays between photoemission from conduction band and core-levels of metal surfaces and metal-metal surfaces in a series of attosecond streaking experiments. We have systematically studied the influence of the screening of streaking fields, electron mean free path, electron localization and XUV chirp on the attosecond streaking photoelectron spectrum profile and time delays. We are extending our model to attosecond time-resolved photoemission with reconstruction of attosecond beating by interference of two-photon transitions (RABBITT) technique on condensed matters. Also, we expect to extend our model to attosecond time-resolved photoemission from more complex systems, such as nanospheres, nanowires and other nanostructure targets. Research Interests Attosecond time-resolved photoemission from atoms and condensed matters Electron correlations in strong-field double ionization Nonlinear optical phenomena in atom-laser interactions Ultrafast electronic dynamics in atoms and molecules driven by strong laser field 2
Publications [1] U. Thumm, Q. Liao, E. M. Bothschafter, F. Süβmann, M. F. Kling, and R. Kienberger, Chapter XIII in: Handbook of Photonics, Volume 1 (Wiley, January 2015). [2] Q. Liao and U. Thumm, Initial-state, mean-free path, and skin-depth dependence of attosecond time-resolved IR-streaked XUV photoemission from single-crystalline magnesium, Physical Review A 89, 033849 (2014). [3] Q. Liao and U. Thumm, Attosecond time-resolved photoelectron dispersion and photoemission time delays, Physical Review Letters 112, 023602 (2014). [4] Q. Tang, Y. Zhou, C. Huang, Q. Liao, and P. Lu, Correlated electron dynamics in nonsequential double ionization of molecules by mid-infrared fields, Optics Express 20, 19580-19588 (2012). [5] Y. Zhou, C. Huang, Q. Liao, and P. Lu, Classical simulations including electron correlations for sequential double ionization, Physical Review Letters 109, 053004 (2012) [6] C. Huang, Z. Li, Y. Zhou, Q. Tang, Q. Liao, and P. Lu, Classical simulations of electron emissions from H + 2 by circularly polarized laser pulses, Optics Express, 20, 11700-11709 (2012). [7] C. Huang, Y. Zhou, Q. Liao, and P. Lu, Imaging molecular structures with high-energy photoelectrons produced by extreme ultraviolet pulses, JOSA B 29, 734-737 (2012). [8] Q. Liao, Y. Zhou, C. Huang, and P. Lu, Multiphoton Rabi oscillations of correlated electrons in strong-field nonsequential double ionization, New Journal of Physics 14, 013001 (2012). [9] Y. Zhou, C. Huang, Q. Liao, W. Hong, and P. Lu, Control the revisit time of the electron wave packet, Optics Letters 36, 2758-2760 (2011). [10] A. Tong, Y. Zhou, C. Huang, Q. Liao, and P. Lu, Enhanced ionization of perpendicularly aligned H-2 in intense fileds, Optics Communications 284, 2505-2508 (2011). [11] A. Tong, Q. Liao, Y. Zhou, and P. Lu, Internuclear-distance dependence of nonsequential double ionization of H 2 in different alignments, Acta Physica Sinica, 3
60, 043301 (2011). [12] C. Huang, Y. Zhou, A. Tong, Q. Liao, W. Hong, and P. Lu, The effect of molecular alignment on correlated electron dynamics in nonsequential double ionization, Optics Express 19, 5627-5634 (2011). [13] Y. Zhou, C. Huang, A. Tong, Q. Liao, and P. Lu, Correlated electron dynamics in nonsequential double ionization by orthogonal two-color pulses, Optics Express 19, 2301-2308 (2011). [14] Y. Zhou, Q. Liao, C. Huang, A. Tong, and P. Lu, Electron Correlation in Nonsequential Double Ionization of Helium by Two-Color Pulses, Chinese Physics Letters, 27 123201 (2010). [15] Y. Zhou, Q. Liao, and P. Lu, Asymmetric electron energy sharing in strong-field double ionization of helium, Physical Review A 82, 053402 (2010). [16] Q. Liao and P. Lu, Energy correlation in above-threshold nonsequential double ionization at 800 nm, Physical Review A, 82, 021403(R) (2010). [17] Y. Zhou, Q. Liao, and P. Lu, Complex sub-laser-cycle electron dynamics in strong-field nonsequential triple ionization, Optics Express 18, 16025-16034 (2010). [18] C. Huang, Q. Liao, Y. Zhou, and P. Lu, Role of Coulomb focusing on the electron transverse momentum of above-threshold ionization, Optics Express 18, 14293-14300 (2010). [19] Tong A., Liao Q., Zhou Y., and P. Lu, Internuclear-distance dependence of electron correlation in nonsequential double ionization of H 2, Optics Express 18, 9064-9070 (2010). [20] Y. Zhou, Q. Liao, Q. Zhang, W. Hong and P. Lu, Controlling nonsequential double ionization via two-color few-cycle pulses, Optics Express 18, 632-638 (2010). [21] Q. Zhang, P. Lu, W. Hong, Q. Liao, and S. Wang, Control of high-order harmonic generation from molecules lacking inversion symmetry with a polarization gating method, Physical Review A 80, 033405 (2009). [22] Q. Liao and P. Lu, Manipulating nonsequential double ionization via alignment of asymmetric molecules, Optics Express 17, 15550-15557 (2009). [23] Y. Zhou, Q. Liao, and P. Lu, Mechanism for high-energy electrons in nonsequential 4
double ionization below the recollision excitation threshold, Physical Review A 80, 023412 (2009). [24] Q. Zhang, P. Lan, W. Hong, Q. Liao, Z. Yang, and P. Lu, The effect of controlling laser field on broadband supercontinuum generation, Acta Physica Sinica, 58, 4908-4913 (2009). [25] Q. Zhang, P. Lu, W. Hong, Q. Liao, P. Lan, and X. Wang, Enhanced high-order harmonic generation via controlling ionization in spatially extended systems, Physical Review A 79, 053406 (2009). [26] P. Lan, P. Lu, Q. Liao, Q. Zhang, and Z. Yang, Phase-dependent photoionization in the oversaturation regime, Physical Review A 79, 033820 (2009). [27] Y. Zhou, Q. Liao, P. Lan, and P. Lu, Classical effects of carrier-envelope phase on nonsequential double ionization, Chinese Physical Letters 25, 3950-3953 (2008). [28] Q. Liao, P. Lu, Q. Zhang, Z. Yang, and X. Wang, Double ionization of HeH + molecules in intense laser fields, Optics Express 16, 17070-17075 (2008). [29] Q. Liao, P. Lu, Q. Zhang, W. Hong, and Z. Yang, Phase-dependent nonsequential double ionization by few-cycle laser pulses, Journal of Physics B 41, 125601 (2008). [30] Q. Liao, P. Lu, P. Lan, Z. Yang, and Y. Li, Method to precisely measure the phase of few-cycle laser pulses, Optics Express 16, 6455-6460 (2008). [31] W. Hong, P. Lu, P. Lan, Z. Yang, Y. Li, and Q. Liao, Broadband xuv supercontinuum generaton via controlling quantum paths by a low-frequency field, Physical Review A 77, 033410 (2008). [32] Q. Liao, P. Lu, P. Lan, W. Cao, and Y. Li, Phase dependence of high-order above-threshold ionization in asymmetric molecules, Physical Review A 77, 013408 (2008). 5