Liu Yikun, Wu You, Chen Chun-Wei, Zhou Jianying, Lin Tsung-Hsien, Khoo Iam Choon
Opt Express. 2016 May 16;24(10):10458-65. doi: 10.1364/OE.24.010458.
We have experimentally demonstrated the feasibility of direct compression, or stretching and recompression of laser pulses in a very wide temporal time scale spanning 10's fs to ~1 ps time with sub-mm thick cholesteric liquid crystal (CLC) cells. The mechanisms at work here are the strong dispersion at the photonic band-edges and nonlinear phase modulation associated with the non-resonant ultrafast molecular electronic optical nonlinearity. The observed pulse compression limit, spectral characteristics and intensity dependence of the compression are in good agreement with theoretical expectations and simulations based on a coupled-mode propagation model. Owing to the large degree of freedom to engineer the wavelength locations of CLC photonic bandgap and band-edges, these self-action all-optical processes can be realized with ultrafast lasers pulses in a very wide spectral region from the visible to near infrared, with potential applications in compact ultrafast photonic modulation devices/platforms.
我们通过实验证明了使用亚毫米厚的胆甾相液晶（CLC）盒，在从10飞秒到约1皮秒的非常宽的时间尺度上直接压缩或拉伸并重新压缩激光脉冲的可行性。这里起作用的机制是光子带边处的强色散以及与非共振超快分子电子光学非线性相关的非线性相位调制。观察到的脉冲压缩极限、光谱特性以及压缩的强度依赖性与基于耦合模传播模型的理论预期和模拟结果高度吻合。由于在设计CLC光子带隙和带边的波长位置方面有很大的自由度，这些自作用全光过程可以在从可见光到近红外的非常宽的光谱区域内用超快激光脉冲实现，在紧凑型超快光子调制器件/平台中具有潜在应用。
