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The physical process of stimulated Raman scattering (SRS) in the diamond and the performance of the Raman laser in the multi-phonon absorption band of 2.5–3 μm were theoretically studied. A theoretical model for the external-cavity diamond Raman laser emitting at the waveband was built based on the Raman coupled-wave equation and boundary conditions. Raman laser output characteristics such as lasing threshold, input–output, and temporal behavior of Stokes conversion were investigated and theoretically simulated by varying the values of the length of the diamond and the transmittance of the output coupler. The numerical modeling shows that to reduce the impact of the multi-phonon absorption and obtain a higher conversion efficiency, it is necessary to appropriately increase the output coupling of the cavity. Taking the 3 μm diamond Raman laser optimization as an example, it is predicted that the conversion efficiency of 10% could be obtained with a diamond length of 1 cm, a transmittance of 69%, and a pump intensity of 1.2 GWcm−2. The theoretical model also could be used to investigate other wavelengths of the external-cavity diamond Raman laser and be helpful for the optimum design of diamond Raman lasers in the mid-infrared band.

A new multi-functional crystal has been implemented by combining the acousto-optic (A/O) modulation with Raman laser output, which has never reported before. Notably, the $\alpha $ -BTM displaying an adequate A/O figure of merit of $10.18\times 10^{-18}\,\,\text{s}^{3}$ /g using the comparison method is originally tailored to fabricate an A/O modulator that exhibits a high diffraction angle and diffraction efficiency of 1.432° and 82.1% at 1064 nm, respectively, which can be competitive with that of TeO2. Pumped by a pulsed laser, sequentially, the self-Q-switch Raman laser working at 1178.1 nm is successfully realized based on $\alpha $ -BTM crystal. A maximum output power of 86 mW operating at 1178.1 nm and the repetition frequency of 15 kHz were obtained with the pump power of 27 W. Our works not only enrich the family of A/O materials, but also opens up a viable route towards exploiting the design of multi-functional crystal. [ABSTRACT FROM AUTHOR]

We have studied an all solid-state diode-side-pumped laser which lases in the nominally eye-safe spectral range of ~1.5-1.6 μm. The optical configuration of the laser is based on using a potassium gadolinium tungstate crystal doped with neodymium ions, in which lasing occurs at a wavelength of λ = 1.351 μm and stimulated Raman selfconversion occurs to the first Stokes component (λ = 1.538 μm). The maximum output pulse energy was 17 mJ and 7 mJ for repetition frequencies of respectively 1 Hz and 10 Hz. [ABSTRACT FROM AUTHOR]