【摘要】 提出了一种新的两级非共线相位匹配光参量放大方案,两级光参量放大分别采用不同的相位匹配条件,充分利用非线性晶体的相位匹配能力和增益光谱范围,可以实现增益带宽接近一个倍频程的光参量放大。并以4.5 mm厚的偏硼酸钡(BBO)晶体和波长为532 nm、强度为5 GW/cm2的抽运光源为例进行了模拟计算,结果表明,该方案可以实现波长范围在710~1190 nm、增益带宽为480 nm的信号光放大,信号光光谱宽度达到0.75个倍频程,再压缩后傅里叶限脉冲的时间宽度约为5 fs,约等于1.6倍的光振荡周期。计算了光参量放大过程中的相位畸变,以及该相位畸变对再压缩后信号光脉冲时间波形的影响。研究结果可以为实现周期量级光参量放大的设计提供理论依据。更多还原

【Abstract】 A new two- stage noncollinear phase- matching optical parametric amplification(OPA) scheme,which can make full use of the phase- matching capability and the spectral gain range of specific nonlinear crystal to amplify neighboring spectral components of the seed by using individual phase-matching geometry in two- stage OPAs, is proposed to achieve a gain bandwidth close to one octave bandwidth. Numerical simulations are performed, in the case of a 4.5 mm-thick β-Ba B2O4(BBO) crystal and a laser pump source with wavelength of 532 nm and intensity of 5 GW/cm2. The results show that this scheme allows for an amplification of 480 nm spectral width spanning from 710 nm to 1190 nm corresponding to 0.75 octave bandwidth with a Fourier limited pulse duration of 5 fs, which equals to 1.6 times of the period of light oscillation. The phase distortions from parametric gain process and its impact on the temporal profile of the recompressed signal pulse are calculated. Results presented are capable of providing a theoretical basis for the design of optical parametric amplification system allowing for the generation of single-cycle pule.更多还原