We report generation of a visible and near-infrared supercontinuum from a high-gain, ultra-broadband, and mirrorless Raman oscillator in a monolithic KTP crystal. The plane transverse to the pump axis resonates and traps off-axis Stokes waves and their frequency-upconverted components bouncing between two crystal surfaces via total internal reflection. The Raman gain is maximized with the Stokes polarization perpendicular to the plane of reflections. When pumped by a ${Q}$-switched Nd:YAG laser, the monolithic oscillator generates quasi-mode-locked Stokes pulses with octave-spanning spectral groups across the visible and near-infrared spectra between 540 and 1800 nm.

中文翻译：

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从单片 KTP 晶体中的离轴拉曼振荡产生八度跨度超连续谱

我们报告了从单片 KTP 晶体中的高增益、超宽带和无反光镜拉曼振荡器产生可见光和近红外超连续谱。与泵轴垂直的平面共振并捕获离轴斯托克斯波及其频率上变频分量通过全内反射在两个晶体表面之间反弹。拉曼增益在斯托克斯偏振垂直于反射平面的情况下最大化。当由${Q}$开关 Nd:YAG 激光器泵浦时，单片振荡器在 540 和 1800 nm 之间的可见光和近红外光谱中产生具有倍频程跨度光谱组的准锁模斯托克斯脉冲。