Kudryashov S I, Levchenko A O, Danilov P A, Smirnov N A, Ionin A A
Opt Lett. 2020 Apr 1;45(7):2026-2029. doi: 10.1364/OL.389348.
Single microscale filaments were produced in monocrystalline Ia-type diamond by 1030 nm, 300 fs laser pulses tightly focused at NA = 0.3 and different peak powers, visualized by transverse imaging and spectrally characterized by longitudinal micro-spectroscopy, using intrinsic UV A-band photoluminescence (PL) with its peak at about 430 nm. Power-dependent scaling relationships for the local PL yield and diameters of the accompanying luminous micro-channels of recombining electron-hole plasma indicate a transition from three-photon absorption to free-carrier plasma absorption, as the consequent energy deposition mechanisms at increasing peak laser power. Power-dependent elongation of the luminous micro-channels versus peak laser power fitted by a Marburger formula yields, on average a diffraction-based estimate of 0.6 MW critical power for self-focusing within the diamond at the pump laser wavelength of 1030 nm.
通过将1030纳米、300飞秒的激光脉冲紧密聚焦在数值孔径为0.3且具有不同峰值功率的条件下，在单晶Ia型金刚石中产生了单根微尺度细丝。通过横向成像对其进行可视化，并利用峰值位于约430纳米处的本征紫外A带光致发光（PL），通过纵向显微光谱对其进行光谱表征。伴随复合电子 - 空穴等离子体的发光微通道的局部PL产率和直径的功率依赖缩放关系表明，随着峰值激光功率增加时随之而来的能量沉积机制，从三光子吸收转变为自由载流子等离子体吸收。发光微通道的功率依赖伸长与峰值激光功率通过马尔堡公式拟合，平均得出在1030纳米泵浦激光波长下金刚石内自聚焦的基于衍射的临界功率估计值为0.6兆瓦。
