高功率飞秒光梳精密控制与应用探索

发布时间：2019-02-28 12:04

【摘要】：基于锁模飞秒脉冲时-频域精密控制的光学频率梳在超快激光领域引发了重要的技术革新。飞秒光梳输出激光具有良好的相干性与频率精确度,并能够实现覆盖一个倍频程的宽带光谱输出。如果将飞秒光梳的某一根梳齿锁定到稳定的窄线宽连续光源上,则可以形成窄线宽光梳并完成频率的精密传递。另一方面,通过激光放大器提升超短脉冲的峰值能量,可以增强光梳输出激光的探测灵敏度,从而将高功率飞秒光梳系统运用到诸如紫外与中红外频段拓展、阿秒脉冲产生、天文光谱仪校准、精密光谱与距离测量、微波光子学等前沿科学研究中。围绕着“高功率飞秒光梳精密控制与应用探索”这一主题,本论文依次从光梳种子源振荡器的优化、超短脉冲功率放大、高功率脉冲载波包络相位探测与相位噪声抑制等方面展开了深入研究与分析讨论,实现了脉冲平均功率100 W,峰值功率15 MW的自相似脉冲放大系统;并进而利用基于声光移频器的前向式反馈控制技术对高功率脉冲进行载波包络相位控制,获得了平均功率50 W,脉冲宽度54 fs的掺镱光纤光学频率梳系统。该系统中受控的载波包络相位信号线宽为11 mHz,累积相位噪声为1.25 rad。此外,研究中继而开展了时-频域精密控制的高功率光梳在特殊非线性光学现象激发与光学精密测量等方面的应用探索。本文的主要研究内容和创新点总结如下1.优化光纤光学频梳种子源的结构特性,在非线性偏振旋转锁模激光器的基础上发展基于法拉第旋转器的偏振补偿式色散控制技术,从而有效降低腔内光栅的衍射损耗并提高激光器的结构稳定性,在约48 mW的锁模阂值下获得了脉宽55 fs,峰值功率2.9 kW的近红外超短脉冲；开展光纤激光器中的波形控制研究,利用腔内自相位调制效应实现具有较高自由运转频率精度的自相似脉冲,为后续超短脉冲高功率放大和光梳载波包络相位噪声的长期抑制提供稳定光源。2.研制超短脉冲光纤功率放大器,利用基于全光纤时域展宽器的啁啾脉冲放大系统实现泵浦斜效率为62%,最大平均输出功率值为270 W,单脉冲能量为4.5μJ的基模高功率脉冲输出,压缩后的超短脉冲具有625 fs的时间宽度,脉冲峰值功率为4.3 MW；发展自相似放大技术,克服超短脉冲放大过程中的非线性效应与有限增益带宽制约的难题,通过预啁啾管理方案加速增益光纤内超短脉冲演变,实现了压缩后平均功率为90 W,脉冲宽度为60 fs,峰值功率为15 MW的超短脉冲输山。该平均功率值是已报道同类放大技术最大输出功率的5倍,为高功率飞秒光梳系统提供可靠驱动源。3.开展新型放大材料的激光特性研究,利用无水基流延成型法制备新型Yb：YAG透明陶瓷激光介质,并得到腔内直接输出功率为7 W,泵浦转换效率达到60.2%的高功率连续光输出与平均功率450 mW,时域3 ps的脉冲光输出；同时,利用该固体脉冲激光器作为种子源,在非线性光纤放大系统中获得最大平均功率为100 W,脉度为70 fs,光谱范围超过85 nm的高质量宽带超短脉冲输出,为研制基于块状增益介质的新一代集成化高功率飞秒光梳开辟道路。4.实现高功率超短脉冲的时频域精密操控,获得平均功率50W,脉冲宽度54 fs的高功率光学频率梳系统。利用基于声光移频器的前馈式相位噪声抑制技术对脉冲载波包络相位进行精确锁定,受控的载波包络相位信号线宽达到11mHz,累积相位噪声为1.25 rad,载波与包络的相对时间抖动量为418 as,连续锁定时间超过1小时。利用锁相环电子反馈系统将脉冲重复频率的长期频率漂移量被稳定在±3 mHz的范围内,频率精度标准偏差达到0.795 mHz。该光梳系统的平均功率水平达到了前向反馈式光学频率梳的最高水平5.在高功率飞秒光梳的应用探索中,利用高功率超短脉冲激发光子晶体光纤中耗散孤子增强、光极化和二次谐波产生等综合性非线性作用,获得最短波长在300nm,转换范围超过100 nm的宽带倍频紫外光；首次利用飞秒光梳作为参考源探测连续激光器输出线宽,使光纤单频激光器和外腔半导体激光器的测量结果达到了行业内领先水平；同时,对基于双光梳测量技术的光谱遥感系统进行了原理性实验验证,在扫描时间0.1 ms内获得较高分辨率精度的距离测量结果。
[Abstract]:The optical frequency comb based on the mode-locked femtosecond pulse-frequency domain precision control has caused important technological innovation in the ultrafast laser field. The femtosecond optical comb output laser has good coherence and frequency accuracy, and can realize wide-band spectral output covering one octave. If one of the comb teeth of the femtosecond optical comb is locked to a stable narrow line-width continuous light source, a narrow line-width optical comb can be formed and the precise transmission of the frequency can be completed. on the other hand, the peak energy of the ultrashort pulse is improved by the laser amplifier, the detection sensitivity of the light comb output laser can be enhanced, Precision spectrum and distance measurement, microwave photonics, etc. in the scientific research. In this paper, the research and analysis of the optical comb seed source oscillator, the ultra-short pulse power amplification, the high power pulse carrier envelope phase detection and the phase noise suppression are carried out in this paper in turn, and the pulse average power 100W is realized. A self-similar pulse amplifying system with a peak power of 15 MW is used, and then the carrier envelope phase control is carried out on the high power pulse by the forward feedback control technology based on the acousto-optic frequency shifter, and the optical frequency comb system of the doped optical fiber with the average power of 50 W and the pulse width of 54 fs is obtained. The controlled carrier envelope phase signal line in the system is 11 mHz and the cumulative phase noise is 1.25 rad. In addition, the application of high-power optical comb in time-frequency domain precision control in special nonlinear optical phenomena excitation and optical precision measurement is also carried out in the research. The main research and innovation points of this paper are summarized as follows. the polarization compensation type dispersion control technology based on the Faraday rotator is developed on the basis of the non-linear polarization rotary mode-locked laser, so that the diffraction loss of the cavity in the cavity is effectively reduced and the structural stability of the laser is improved, A near-infrared ultra-short pulse with a pulse width of 55 fs and a peak power of 2.9 kW was obtained at a value of approximately 48 mW, and a self-similar pulse with higher free-running frequency accuracy was realized by using the self-phase modulation effect in the cavity. And provides a stable light source for the long-term inhibition of the subsequent ultrashort pulse high power amplification and the phase noise of the optical comb carrier envelope. the ultra-short pulse fiber power amplifier is developed, the pumping efficiency is 62%, the maximum average output power value is 270W, and the single pulse energy is 4.5. m the compressed ultrashort pulse has a time width of 625fs, the pulse peak power is 4.3 MW, the self-similar amplification technology is developed, the problem that the nonlinear effect in the ultrashort pulse amplification process and the limited gain bandwidth is overcome, The ultra-short pulse evolution in the gain optical fiber is accelerated by the pre-pulse management scheme, and the ultra-short pulse transmission hill with the average power of 90W, the pulse width of 60 fs and the peak power of 15 MW is realized. The average power value is 5 times the maximum output power of the similar amplification technology, and provides a reliable driving source for the high-power femtosecond optical comb system. A new type of Yb: YAG transparent ceramic laser medium was prepared by the method of anhydrous base flow, and the direct output power of the cavity was 7W, and the output of the high power continuous light with the pump conversion efficiency of 60.2% and the average power of 450 mW were obtained. and simultaneously, using the solid-pulse laser as a seed source, a high-quality broadband ultrashort pulse output with a maximum average power of 100 W, a pulse degree of 70 fs and a spectral range of more than 85 nm is obtained in a non-linear optical fiber amplification system, In order to open up a new generation of integrated high-power femtosecond optical comb based on block-like gain medium. And the high-power optical frequency comb system with the average power of 50W and the pulse width of 54fs is obtained when the high-power ultra-short pulse is realized. the pulse carrier envelope phase is accurately locked by a feed-forward phase noise suppression technology based on an acousto-optic frequency shifter, the controlled carrier envelope phase signal line width reaches 11 mHz, the accumulated phase noise is 1.25 rad, and the relative time jitter amount of the carrier wave and the envelope is 418as, The continuous locking time is more than 1 hour. Using a phase-locked loop electronic feedback system, the long-term frequency drift of the pulse repetition frequency is stabilized in the range of about 3 mHz, and the standard deviation of the frequency accuracy reaches 0.795 mHz. The average power level of the optical comb system reaches the highest level 5 of the forward feedback optical frequency comb. In the application of high-power femtosecond optical comb, the broadband frequency-doubled ultraviolet light with the shortest wavelength of 300 nm and the conversion range of more than 100 nm is obtained by using high-power ultra-short pulse to excite the comprehensive non-linear effects of the dissipation soliton enhancement, the optical polarization and the second harmonic generation in the photonic crystal fiber. In the first time, a femtosecond optical comb is used as a reference source to detect the output line width of a continuous laser, so that the measurement results of the optical fiber single frequency laser and the external cavity semiconductor laser reach the leading level in the industry; meanwhile, the spectral remote sensing system based on the double light comb measurement technology is verified by the principle experiment, A distance measurement result of higher resolution accuracy is obtained in a scan time of 0.1 ms.
【学位授予单位】：华东师范大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：O437

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