High-power continuous-wave single-frequency diamond Raman laser at 1178 nm

Abstract

We demonstrate a continuous-wave single-frequency diamond Raman laser operating at 1178 nm by using a linear resonator that is stabilized using an intracavity [Formula: see text] element. Optimization of the single-frequency power was realized by tuning the phase matching in the [Formula: see text] element away from the second-harmonic peak to suppress neighboring modes via sum frequency generation but avoid large losses to the intracavity primary Stokes mode. A maximum single-longitudinal-mode power of 20 W at 1178 nm with an instrument-limited linewidth of 67 MHz was obtained using a 12 GHz multi-longitudinal-mode Yb-doped fiber pump laser at 1018 nm with power of 82 W. This work provides an interesting route for producing single-frequency high-power lasers near 1.2 μm utilizing diamond Raman conversion combined with broadband, high-power, low-cost YDF lasers.

High-power free-running single-longitudinal-mode diamond Raman laser enabled by suppressing parasitic stimulated Brillouin scattering

“…The parasitic SBS was converted from the narrow-linewidth Raman laser, which could result in Raman power depletion and SLM instability. Approaches including the intracavity etalon [28] , aperture [23] and nonlinear mode loss methods [13] were proposed to suppress the parasitic higher-order SBS spatial modes. In our case, to diminish the SBS gain and suppress higher-order spatial SBS oscillation, the cavity length was delicately adjusted by tuning M3 and simultaneously the intracavity pump-Raman interaction region was moved to the edge of the diamond crystal, which could be regarded as an aperture for higher modes.…”

“…The laser was multimode for higher powers, which was attributed to mode destabilization via strong coupling between the laser power and the cavity length. SLM stabilization techniques, such as intracavity volume Bragg grating [ 1 ] , cavity locking [ 20 ] and introducing nonlinear loss [ 13 , 23 , 25 ] , have been used to improve the SLM diamond Stokes output power. A maximum Stokes power of 20 W at 1178 nm in a linear standing-wave resonator was demonstrated recently [ 13 ] by using an intracavity crystal to increase mode competition [ 26 ] .…”

“…SLM stabilization techniques, such as intracavity volume Bragg grating [ 1 ] , cavity locking [ 20 ] and introducing nonlinear loss [ 13 , 23 , 25 ] , have been used to improve the SLM diamond Stokes output power. A maximum Stokes power of 20 W at 1178 nm in a linear standing-wave resonator was demonstrated recently [ 13 ] by using an intracavity crystal to increase mode competition [ 26 ] . However, power limits for intrinsic SLM stability have not been fully tested and are not yet well understood.…”

“…Wavelength flexible narrow-linewidth single-frequency lasers, credited to the precise wavelength and towering coherence, are valuable for a variety of applications, including laser sensing, quantum technology, coherent detection and astronomical observation [1][2][3][4][5] . Lasers based on the χ (3) nonlinear gain of the stimulated Raman scattering (SRS) are an effective way to expand the wavelength range of single-frequency lasers as well as a path to acquire high output power [6][7][8][9][10][11][12][13][14] . This is achieved without consideration of the stringent phase matching conditions integral to efficient χ (2) interactions, such as optical parametric oscillation, second harmonic generation and sum frequency generation.…”

A review of ns-pulsed Raman lasers based on diamond crystal

“…[50], including the non-spatial-holeburning effect of Raman gain, cavity locking, intracavity nonlinear gain competition, and inserting mode selection elements. However, the SLM DRLs were all operating in CW or Q-CW [19,32,[51][52][53].…”