Zhong Haizhe, Qin Fen, Liang Yuhai, Yang Jianlong, Wang Shiwei, Li Ying, Fan Dianyuan
Opt Express. 2017 Feb 6;25(3):2529-2539. doi: 10.1364/OE.25.002529.
Synchronously pumped optical parametric oscillator (OPO) at degeneracy is ideal for generating ultrafast laser pulses. Normally, however, group velocity mismatch (GVM) is ubiquitous among the interacting pulses at widely separated wavelengths. A versatile quasi-phase-matching (QPM) technique is proposed for temporal synchronizing of the signal and idler pulses relied on a less common Type-II QPM (oe-o interaction). The proposed group-velocity regulation technology is advantageous to constructing a degeneracy-analogous femtosecond OPO for dual-wavelength operation. Qualitative prediction for the proposed design is conducted based on a commercial femtosecond pump source at 1064 nm while the signal/idler wavelengths are 3.2 μm and 1.59 μm respectively. Compared with the conventional Type-0 QPM based counterpart (ee-e interaction), the uncompensated temporal distortion caused by temporal walk-off is strongly suppressed while the idler spectrum gets significantly broader. The versatility of the proposed scheme is also clearly demonstrated by its fairly stable performance within a broad tuning range of 2.9-3.5 μm and 1.68-1.53 μm. The demonstrated configuration might be promising for synchronously obtaining dual-wavelength ultrafast pulses with higher spectral and temporal qualities.
简并态同步泵浦光学参量振荡器（OPO）是产生超快激光脉冲的理想选择。然而，通常情况下，在波长相差较大的相互作用脉冲之间普遍存在群速度失配（GVM）。本文提出了一种通用的准相位匹配（QPM）技术，用于基于不太常见的II型QPM（oe - o相互作用）对信号脉冲和闲频脉冲进行时间同步。所提出的群速度调节技术有利于构建用于双波长运行的类简并飞秒OPO。基于1064 nm的商用飞秒泵浦源进行了所提设计的定性预测，此时信号/闲频波长分别为3.2μm和1.59μm。与基于传统0型QPM（ee - e相互作用）的对应方案相比，由时间走离引起的未补偿时间畸变得到了强烈抑制，同时闲频谱显著变宽。所提方案的通用性还通过其在2.9 - 3.5μm和1.68 - 1.53μm的宽调谐范围内相当稳定的性能得到了清晰展示。所展示的配置对于同步获得具有更高光谱和时间质量的双波长超快脉冲可能具有前景。
