物理学报
物理學報
물이학보
2013年
9期
217-223
,共7页
倾斜波%级联二阶非线性%群速度失配%脉冲压缩
傾斜波%級聯二階非線性%群速度失配%脈遲壓縮
경사파%급련이계비선성%군속도실배%맥충압축
tilt pulse%cascaded quadratic nonlinearity%group velocity mismatch%pulse compression
提出了一种采用倾斜脉冲的级联二阶非线性来实现超短激光脉冲压缩的方法.对基于单块BBO晶体中基频光与倍频光群速度匹配的级联二阶非线性的脉冲压缩方案进行了理论分析.对比研究了群速度匹配与失配情况下利用级联二阶非线性进行脉冲压缩的效果,并模拟分析了基频光与倍频光的位相失配量、非线性晶体长度、基频光初始峰值光强和初始脉宽等因素对脉冲压缩效果的影响.结果表明,基频光与倍频光的群速度匹配将会大幅度改善压缩脉冲的时间波形和频谱分布.通过对位相失配量、晶体长度、初始光强等参数的优化和选取可获得较理想的压缩效果.采用倾斜脉冲的级联二阶非线性的脉宽压缩方法,针对中心波长800 nm、脉宽100 fs,峰值光强为50 GW/cm2的基频光脉冲,采用25 mm厚BBO晶体,当基频光与倍频光位相失配量?k=60 mm?1(对应失谐角1.98?),晶体外部脉冲前沿倾斜角γ0=74?时,计算获得了质量较好的20 fs剩余基频光,并同时产生了14 fs的倍频光.
提齣瞭一種採用傾斜脈遲的級聯二階非線性來實現超短激光脈遲壓縮的方法.對基于單塊BBO晶體中基頻光與倍頻光群速度匹配的級聯二階非線性的脈遲壓縮方案進行瞭理論分析.對比研究瞭群速度匹配與失配情況下利用級聯二階非線性進行脈遲壓縮的效果,併模擬分析瞭基頻光與倍頻光的位相失配量、非線性晶體長度、基頻光初始峰值光彊和初始脈寬等因素對脈遲壓縮效果的影響.結果錶明,基頻光與倍頻光的群速度匹配將會大幅度改善壓縮脈遲的時間波形和頻譜分佈.通過對位相失配量、晶體長度、初始光彊等參數的優化和選取可穫得較理想的壓縮效果.採用傾斜脈遲的級聯二階非線性的脈寬壓縮方法,針對中心波長800 nm、脈寬100 fs,峰值光彊為50 GW/cm2的基頻光脈遲,採用25 mm厚BBO晶體,噹基頻光與倍頻光位相失配量?k=60 mm?1(對應失諧角1.98?),晶體外部脈遲前沿傾斜角γ0=74?時,計算穫得瞭質量較好的20 fs剩餘基頻光,併同時產生瞭14 fs的倍頻光.
제출료일충채용경사맥충적급련이계비선성래실현초단격광맥충압축적방법.대기우단괴BBO정체중기빈광여배빈광군속도필배적급련이계비선성적맥충압축방안진행료이론분석.대비연구료군속도필배여실배정황하이용급련이계비선성진행맥충압축적효과,병모의분석료기빈광여배빈광적위상실배량、비선성정체장도、기빈광초시봉치광강화초시맥관등인소대맥충압축효과적영향.결과표명,기빈광여배빈광적군속도필배장회대폭도개선압축맥충적시간파형화빈보분포.통과대위상실배량、정체장도、초시광강등삼수적우화화선취가획득교이상적압축효과.채용경사맥충적급련이계비선성적맥관압축방법,침대중심파장800 nm、맥관100 fs,봉치광강위50 GW/cm2적기빈광맥충,채용25 mm후BBO정체,당기빈광여배빈광위상실배량?k=60 mm?1(대응실해각1.98?),정체외부맥충전연경사각γ0=74?시,계산획득료질량교호적20 fs잉여기빈광,병동시산생료14 fs적배빈광.
A new method for compressing ultra-short laser pulse has been proposed in which cascaded quadratic nonlinearity with tilt pulse is used. The pulse compression scheme with group velocity matching between fundamental harmonic (FH) and second harmonic (SH) pulses in a single BBO crystal has been analyzed theoretically. The compressed results have been investigated and compared between the cases of group velocity matching and mismatching. Furthermore, the influences of the phase mismatching between the FH and SH pulses, the length of the nonlinear crystal, the initial peak intensity and pulse-duration of the FH pulse on the pulse-duration compression have been analyzed and simulated. The results show that the matched group velocity between FH and SH pulses can improve significantly both the temporal profile and the spectrum distribution of the compressed pulse. High quality compression can be achieved by optimizing and selecting the parameters such as phase mismatch, length of the nonlinear crystal, initial intensity and so on. For the fundamental pulse with 800 nm central wavelength, 100 fs duration and 50 GW/cm2 peak intensity, the 20fs output FH pulse has been achieved, and at the same time the 14 fs SH pulse has also been generated in 25 mm-long BBO crystal with?k=60 mm?1 (1.98?detuning angle) and external tilt angleγ0=74?.
