A novel Nd:YAG thin-disk laser with excellent cooling configuration is demonstrated. A maximum output energy of 653 mJ is realized, corresponding to the optical–optical efficiency of 30% and the slope efficiency of 35%. The coefficient of output instability is as low as 1.1% at a repetition rate of 1 Hz. Beam propagation analysis reveals that beam distortion caused by temperature gradient will decrease effectively with this laser configuration.

In this Letter, a miniature wearable Raman spectroscopy system is developed. A wearable fiber-optic probe is employed to help the stable and convenient collection of Raman spectra. A nonlinear partial least squares model based on a multivariate dominant factor is employed to predict the glucose level. The mean coefficients of determination are 0.99, 0.893, and 0.844 for the glucose solution, laboratory rats, and human volunteers. The results demonstrate that a miniature wearable Raman spectroscopy system is feasible to achieve the noninvasive detection of human blood glucose and has important clinical application value in disease diagnosis.

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A double-sided liquid cooling Nd:YAG disk oscillator working at a pump repetition rate of 20 Hz is demonstrated. The output energy of 376 mJ is realized, corresponding to the opticaloptical efficiency of 12.8% and the slope efficiency of 14%. The pump pulse width is 300 µs and the laser pulse width is 260 µs. Instead of being a damped signal, the output of laser comprises undamped spikes. A periodic intra-cavity loss was found by numerical analysis, which has a frequency component near the eigen frequency of the relaxation oscillation. Resonance effect will induce amplified spikes even though the loss fluctuates in a small range. The Shark-Hartmann sensor was used to investigate the wavefront aberration induced by turbulent flow and temperature gradient. According to the wavefront and fluid mechanics analysis, it is considered that the periodic intra-cavity loss can be attributed to turbulent flow and temperature gradient.