19飞秒激光脉冲的产生与测量

本文介绍产生19飞秒激光脉冲的被动锁模四棱镜补偿群速度分散的环型染料激光器的特点;讨论了二次谐波强度自相关法和二次谐波干涉自相关法。用该激光器产生的超短而高稳定的光源对同步扫描条纹相管作了评价。

GENERATION AND MEASUREMENT OF 19 FEMTOSECOND LIGHT PULSES

This presentation will discuss the performance characteristics of a passively mode-locked dye laser.It is well known that in order to generate pulses in the tens of femtosecond range it is imperative to balance self-phase modulation(SPM)with adjusting intracavity group velocity dispersion (GVD).We describe a seven-mirror ring cavity configuration which has a four-prism arran-gement.All the cavity reflectors M1-M7 have single-stack didearic coatings that combine to re-stric laser operation to wavelengths in excess of 600nm.The active Rhodamine 6G(1.9×10^-3M)and passive Diethyloxadicarbocyanine iodide(DODCI.2.7×10^-4 M)disolved in ethylene glycol flow through standard commercial nozzles of250μm in a horizontal orientation,respectively.The plane of a prism sequence was vertical in our cavity configuration.The gain medium was pumped by Argon laser green beam. When no absorber is present the operation wavelength is 604nm, whereas the wavelength when mode-locked is typically 630nm.The shortest pulse duratons we got were19fs.The exprimental and theoritical data show that for pulse duration of less than 100fs, the intensity profiles of light could be described by an asymmetric sech² function: I(t)=(exp(-t)+exp(rt))^-2 The second harmonic intensity and mterferometric autocorrelation techniques which were used to measure pulse durations are also discussed.Finally we discuss the method of the evaluation of synchroscan streak tube performances,using these short and stable pulses generated directly from this laser.