Nonlinear frequency generation requires high intensity density which is usually achieved with pulsed laser sources, anomalous dispersion, high nonlinear coefficients or long interaction lengths. Whispering gallery mode microresonators (WGMRs) are photonic devices that enhance nonlinear interactions and can be exploited for continuous wave (CW) nonlinear frequency conversion, due to their capability of confine light for long time periods in a very small volume, even though in the normal dispersion regime. All signals must be resonant with the cavity. Here, we present a review of nonlinear optical processes in glass microspherical cavities, hollow and solid.

中文翻译：

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微球谐振器中的非线性光学

非线性频率的产生需要高强度密度，这通常是通过脉冲激光源，反常色散，高非线性系数或较长的相互作用长度来实现的。回音壁模式微谐振器（WGMR）是一种光子器件，可增强非线性相互作用，并且由于能够将光长时间限制在很小的体积（即使在正常情况下），因此可以用于连续波（CW）非线性频率转换。分散制度。所有信号必须与腔谐振。在这里，我们对中空和实心玻璃微球腔中的非线性光学过程进行综述。