1、Ultrafast Laser Technology and Spectroscopy,1.History,Oscillator technology: 1980s, colliding-pulse mode-locked (CPM) dye laser, 100fs, 30fs, 6fs 1990s,self mode-locking in Ti:sapphire-based lasers, 10-20fsChirped pulse amplification: regenerative amplification multi-pass amplification,colliding-pul
2、se mode-locked (CPM) dye laser,self mode-locking in Ti:sapphire-based lasers,2.Ultrafast Lasers and Amplifier,2.1 Oscillator,2.2 Dispersion and pulse broadening,问题: 1.飞秒激光介质,主要是晶体材料 2.主动锁模和被动锁模技术 3.碰撞脉冲锁模 4.自锁模 5.饱和吸收体(染料、半导体等) 6.色散补偿(棱镜、光栅、啾啾镜) 7.宽带反射镜 8.谐振腔结构,2.3 Chirped-pulse amplification,2.4 Pu
3、lse recompression,Gain cross-section, is not constant as a function of wavelength Pulse narrowing a shift in the central wavelengthMaximum bandwidth to 47nm in Ti:sapphire,2.5 Saturation effects,问题: 1.展宽器 2.再生放大 3.多通放大 4.饱和效应 5.压缩器 6.脉冲同步 7.TW放大 8.PW放大,3.Wavelength Conversion,3.1 White-light generat
4、ion and the optical Kerr effects,SHG THG FHG - near-to deep-ultravioletBBO LBO KDP,3.2 Generation of ultraviolet and X-rays,Very high harmonic generationDeep-UV, soft X-ray pulseLaser produced plasmasHard X-ray pulse,3.3 Optical parametric amplifier for infrared generation,3.4 Noncollinear optical p
5、arametric amplification,3.4 Terahertz-pulse generation and detection,4.Time-resolved Experiments,4.1 Auto- and cross-correlation,Spider任意脉冲测量,4.2 Pump-probe techniques,问题:,1.自相关 2.交叉相关 3.FROG测量 4.FROG测量的算法 5.Spider测量 6.Spider测量的算法 7.pump-probe测量 8.条纹相机 9.时间分辨光子计数测量,5. Applications,5.1 The study of f
6、ast chemical reactions,5.2 Imaging,5.3 Structure determination: Electron Beams and X-rays,5.4 Coherent control,一、相干控制方法(早期)(单参数): 1.频域的控制技术(spectral-domain technique)1986年 Brumer and Shapiro提出1990年 Chen and Park等实验实现(原子、分子)原理:基于量子力学相干(相干相长或相消) 2.时域的控制技术(time-domain technique)1985年 Tannor and Rice提出1
7、991年 Baumert等实验实现(纳双原子分子)3.绝热控制技术(adiabatic control technique)1988年 Bergmann等通过STIRAPvery large laser energy Rabi oscillations,二、现代量子相干控制方法: 特点:多参数(时间、空间、频谱、偏振等) 困难:特定目的的激光场设计。1983年 Huang 和Ramakrishna等 方法:1988年 Shi, Peirce and Kosloff等提出优化控制理论实现飞秒脉冲时空整形,1.液晶光学空间调制器,三、飞秒脉冲整形方法:,2.声光光学空间偏转器,3.变形镜,The
8、stokes shifts for asymmetric and symmetric modes, 2942cm-1 and 2835cm-1, respectively.,Depth-resonance single-pulse CARS images of a glass capillary plate with 10um holes filled with CH2Br2 (at 577cm-1),问题,1.SLM整形技术 2.声光晶体整形技术 3.变形镜整形技术 4.周期、亚周期脉冲整形 5. Raman相干增强 6.荧光相干增强 7.高次谐波相干增强 8.化学选键 9.遗传算法 10.退火算法,