Physics Department, International Laser Center, MV Lomonosov Moscow State University, Moscow 119992, Russia.
Opt Lett. 2012 Sep 1;37(17):3618-20. doi: 10.1364/OL.37.003618.
Soliton self-frequency shift (SSFS) in a photonic crystal fiber (PCF) pumped by a long-cavity mode-locked Cr:forsterite laser is integrated with second harmonic generation (SHG) in a nonlinear crystal to generate ultrashort light pulses tunable within the range of wavelengths from 680 to 1800 nm at a repetition rate of 20 MHz. The pulse width of the second harmonic output is tuned from 70 to 600 fs by varying the thickness of the nonlinear crystal, beam-focusing geometry, and the wavelength of the soliton PCF output. Wavelength-tunable pulses generated through a combination of SSFS and SHG are ideally suited for coherent Raman microspectroscopy at high repetition rates, as verified by experiments on synthetic diamond and polystyrene films.
受长腔锁模 Cr:forsterite 激光泵浦的光子晶体光纤中的孤子自频移 (SSFS) 与非线性晶体中的二次谐波产生 (SHG) 相结合，可在 20 MHz 的重复率下在 680 到 1800nm 的波长范围内产生可调谐的超短光脉冲。通过改变非线性晶体的厚度、光束聚焦几何形状和孤子 PCF 输出的波长，可将二次谐波输出的脉冲宽度从 70fs 调谐到 600fs。通过 SSFS 和 SHG 的组合产生的波长可调谐脉冲非常适合在高重复率下进行相干拉曼微光谱学，这在对合成金刚石和聚苯乙烯薄膜的实验中得到了验证。
