Precise control of the electric field in double optical gating with few-cycle pulses
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摘要:
为了利用少周期脉冲实现超短孤立阿秒脉冲产生，需要研究双光学选通门技术对少周期光场电场的精密调控。在传统实验中，双光学选通门的调控对象通常是多周期脉冲，在分析中不考虑激光脉冲在介质传播中的高阶色散、倍频效率及倍频电场的精确波形，但这种近似对于少周期脉冲不再适用。本文基于耦合波方程组模型精确模拟了少周期脉冲在非线性晶体中的传播与倍频过程，揭示了色散效应等因素对选通门波形的关键影响。研究表明，当驱动光场为少周期激光脉冲时，双光学选通门的传统电场估算方法已不再适用。少周期脉冲激光具有超宽的频谱，不同波长成分的光相位累计差异导致的群速度失配、相位失配和色散等效应相比于长脉冲会明显很多。对于少周期脉冲，调整偏硼酸钡（BBO）晶体厚度为126.4 μm时，可以得到最佳选通光场。本文提出通过协同调节波片与BBO晶体厚度可以精细调节驱动场与倍频场的相对延迟，实现选通电场及驱动电场的优化，为超短孤立阿秒脉冲的产生提供了有效的参数优化指导。
Abstract:To achieve the generation of ultrashort isolated attosecond pulses using few-cycle pulses, it is necessary to study the precise manipulation of the electric field of few-cycle optical field through double optical gating technology. In conventional experiments, double optical gating typically regulates multi-cycle pulses, and the analysis does not consider (higher-order dispersion during laser propagation in media, second-harmonic conversion efficiency, or the exact waveform of the second-harmonic electric field). However, such approximations are no longer valid for few-cycle pulses. This paper accurately simulates the propagation and second-harmonic generation process of few-cycle pulses in nonlinear crystals based on a coupled-wave equation model, revealing the key influence of dispersion effects and other factors on the gating waveform. The research shows that when the driving light field is a few-cycle laser pulse, the traditional electric field estimation method for double optical gating is no longer applicable. Few-cycle pulse lasers have an ultra-broad spectrum, and effects such as group velocity mismatch, phase mismatch, and dispersion caused by differences in phase accumulation among different wavelength components become significantly more pronounced compared to long pulses. For a few-cycle pulse, the optimal gating light field can be achieved by adjusting the thickness of the beta-barium borate (BBO) crystal in the double optical gating setup to 126.4 μm. This paper proposes that coordinated adjustment of the waveplate and BBO crystal thickness can finely tune the relative delay between the driving field and the second-harmonic field, thereby optimizing both the gating and driving electric fields, providing effective parameter optimization guidance for the generation of ultrashort isolated attosecond pulses.
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Key words:
- isolated attosecond pulses /
- double optical gating /
- few-cycle pulse
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图 1 双光学选通门调控光场示意图。QP1和QP2为石英片，BW为融石英布儒斯特窗片，BBO为β相偏硼酸钡晶体
Figure 1. Schematic diagram of double optical gating technique. QP1 and QP2 are quartz plates, BW is a fused-silica Brewster window, and BBO is a beta-phase barium metaborate crystal for frequency doubling
图 2 瞬态耦合波方程组计算倍频光场强度分布，经过141 μm BBO晶体倍频后的脉冲与SNLO计算得到的光场（a）长脉冲（
$\tau $ =28 fs）；（b）少周期脉冲（$\tau $ =8 fs）分布结果比较Figure 2. Comparison of the intensity profiles of SH optical field calculated with transient coupled-wave equations, the calculated SH pulse after frequency doubling of a 28 fs long pulse through a 141 μm BBO crystal and the optical field calculated by SNLO. (a) For long pulse (
$\tau $ =28 fs); (b) for few-cycle laser pulse ($\tau $ =8 fs)
图 3 实际实验条件下双光学选通门形成的调制光场。不考虑介质色散和BBO倍频过程群速度失配的(a) 驱动电场
${E}_{{\mathrm{d}}} $ ，选通电场${E}_{{\mathrm{g}}} $ ，倍频电场${E}_{{\mathrm{SH}}} $ 和 (c) 叠加电场${E}_{{\mathrm{d+SH}}} $ ；考虑介质色散和BBO倍频过程群速度失配时的(a)${E}_{{\mathrm{d}}} $ 、${E}_{{\mathrm{g}}} $ 、${E}_{{\mathrm{SH}}}$ 及(d) 叠加电场${E}_{{\mathrm{d+SH}}} $ Figure 3. Modulated optical field formed by double optical gating under realistic experimental conditions. Without considering medium dispersion and group velocity mismatch in the BBO frequency-doubling process, (a) the driving field
$ {E}_{{\mathrm{d}}} $ , gating field$ {E}_{{\mathrm{g}}} $ , and SH field$ {E}_{{\mathrm{SH}}} $ and (c) the superimposed electric field$ {E}_{\mathrm{{d+SH}}} $ . When considering medium dispersion and group velocity mismatch in the BBO frequency-doubling process, (b)$ {E}_{\mathrm{{d}}} $ ,$ {E}_{\mathrm{{g}}} $ , and$ {E}_{\mathrm{{SH}}} $ and (d)$ {E}_{{\mathrm{d+SH}}} $ 
图 4 入射脉冲为7 fs时，调节K值时驱动电场、选通电场及倍频电场强度的变化
Figure 4. Under a 7 fs incident pulse, changes in the amplitudes of the driving field, gating field, and second-harmonic electric field when adjusting the K value
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[1] SARTANIA S, CHENG Z, LENZNER M, et al. Generation of 0.1-TW 5-fs optical pulses at a 1-kHz repetition rate[J]. Optics Letters, 1997, 22(20): 1562-1564. doi: 10.1364/OL.22.001562 [2] CHEN X, MALVACHE A, RICCI A, et al. Efficient hollow fiber compression scheme for generating multi-mJ, carrier-envelope phase stable, sub-5 fs pulses[J]. Laser Physics, 2011, 21(1): 198-201. doi: 10.1134/S1054660X11010063 [3] XIAO F, FAN X H, WANG L, et al. Generation of intense sub-10 fs pulses at 385nm[J]. Chinese Physics Letters, 2020, 37(11): 114202. doi: 10.1088/0256-307X/37/11/114202 [4] PICCOLI R, BROWN J M, JEONG Y G, et al. Intense few-cycle visible pulses directly generated via nonlinear fibre mode mixing[J]. Nature Photonics, 2021, 15(12): 884-889. doi: 10.1038/s41566-021-00888-7 [5] LIU Y ZH, CHEN ZH D, YANG S CH, et al. Few-cycle 12.5-GW pulses generated via efficient all-solid-state post-compression from an ytterbium laser[J]. Optics Letters, 2024, 49(24): 6992-6695. doi: 10.1364/OL.542820 [6] WIRTH A, HASSAN M T, GRGURAŠ I, et al. Synthesized light transients[J]. Science, 2011, 334(6053): 195-200. doi: 10.1126/science.1210268 [7] ALQATTAN H, HUI D D, PERVAK V, et al. Attosecond light field synthesis[J]. APL Photonics, 2022, 7(4): 041301. doi: 10.1063/5.0082958 [8] SONG L W, BAI Y, XU R J, et al. Polarization control of terahertz waves generated by circularly polarized few-cycle laser pulses[J]. Applied Physics Letters, 2013, 103(26): 261102. doi: 10.1063/1.4856495 [9] CARNIO B N, ELEZZABI A Y. Investigation of ultra-broadband terahertz generation from sub-wavelength lithium niobate waveguides excited by few-cycle femtosecond laser pulses[J]. Optics Express, 2017, 25(17): 20573-20583. doi: 10.1364/OE.25.020573 [10] WEGER M, MAURER J, LUDWIG A, et al. Transferring the attoclock technique to velocity map imaging[J]. Optics Express, 2013, 21(19): 21981-21990. doi: 10.1364/OE.21.021981 [11] BABUSHKIN I, GALÁN Á J, DE ANDRADE J R C, et al. All-optical attoclock for imaging tunnelling wavepackets[J]. Nature Physics, 2022, 18(4): 417-422. doi: 10.1038/s41567-022-01505-2 [12] YOSHIZAKI R, NAKAO M. Ultrashort pulse laser processing of single crystalline diamond for efficient and smooth grooving with top-hat beam modulation[J]. CIRP Annals, 2023, 72(1): 189-192. doi: 10.1016/j.cirp.2023.04.001 [13] SOLEIMANI M, NANKALI M, DULEY W W, et al. Additive manufacturing processing with ultra-short-pulse lasers[J]. Journal of Manufacturing Processes, 2024, 131: 2133-2163. doi: 10.1016/j.jmapro.2024.10.006 [14] WANG X W, WANG L, XIAO F, et al. Generation of 88 as isolated attosecond pulses with double optical gating[J]. Chinese Physics Letters, 2020, 37(2): 023201. doi: 10.1088/0256-307X/37/2/023201 [15] WANG L, WANG X W, XIAO F, et al. Chirp compensation for generating ultrashort attosecond pulses with 800-nm few-cycle pulses[J]. Chinese Physics Letters, 2023, 40(11): 113201. doi: 10.1088/0256-307X/40/11/113201 [16] WANG X W, XIAO F, WANG J C, et al. Ultrashort isolated attosecond pulse generation with 750-nm free-carrier envelope phase near-infrared pulses[J]. Ultrafast Science, 2024, 4: 0080. doi: 10.34133/ultrafastscience.0080 [17] CORKUM P B. Plasma perspective on strong field multiphoton ionization[J]. Physical Review Letters, 1993, 71(13): 1994-1997. doi: 10.1103/PhysRevLett.71.1994 [18] FERRAY M, L’HUILLIER A, LI X F, et al. Multiple-harmonic conversion of 1064 nm radiation in rare gases[J]. Journal of Physics B: Atomic, Molecular and Optical Physics, 1988, 21(3): L31-L35. doi: 10.1088/0953-4075/21/3/001 [19] PAUL P M, TOMA E S, BREGER P, et al. Observation of a train of attosecond pulses from high harmonic generation[J]. Science, 2001, 292(5522): 1689-1692. doi: 10.1126/science.1059413 [20] HENTSCHEL M, KIENBERGER R, SPIELMANN C, et al. Attosecond metrology[J]. Nature, 2001, 414(6863): 509-513. doi: 10.1038/35107000 [21] CORKUM P B, BURNETT N H, IVANOV M Y. Subfemtosecond pulses[J]. Optics Letters, 1994, 19(22): 1870-1872. doi: 10.1364/OL.19.001870 [22] JULLIEN A, PFEIFER T, ABEL M J, et al. Ionization phase-match gating for wavelength-tunable isolated attosecond pulse generation[J]. Applied Physics B, 2008, 93(2-3): 433-442. doi: 10.1007/s00340-008-3187-z [23] CHANG Z H. Controlling attosecond pulse generation with a double optical gating[J]. Physical Review A, 2007, 76(5): 051403(R). [24] VINCENTI H, QUÉRÉ F. Attosecond lighthouses: how to use spatiotemporally coupled light fields to generate isolated attosecond pulses[J]. Physical Review Letters, 2012, 108(11): 113904. doi: 10.1103/PhysRevLett.108.113904 [25] MASHIKO H, GILBERTSON S, LI CH Q, et al. Double optical gating of high-order harmonic generation with carrier-envelope phase stabilized lasers[J]. Physical Review Letters, 2008, 100(10): 103906. doi: 10.1103/PhysRevLett.100.103906 [26] FENG X M, GILBERTSON S, MASHIKO H, et al. Generation of isolated attosecond pulses with 20 to 28 femtosecond lasers[J]. Physical Review Letters, 2009, 103(18): 183901. doi: 10.1103/PhysRevLett.103.183901 [27] GILBERTSON S, KHAN S D, WU Y, et al. Isolated attosecond pulse generation without the need to stabilize the carrier-envelope phase of driving lasers[J]. Physical Review Letters, 2010, 105(9): 093902. doi: 10.1103/PhysRevLett.105.093902 [28] CHANG Z H. Single attosecond pulse and xuv supercontinuum in the high-order harmonic plateau[J]. Physical Review A, 2004, 70(4): 043802. doi: 10.1103/PhysRevA.70.043802 [29] SHEN Y R. The Principles of Nonlinear Optics[M]. New York: Wiley, 1984. [30] SMITH A V. SNLO Version 80 Nonlinear Optics Code[M] Albuquerque, NM: AS-photonics. -
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