Continuous-wave Watt-level Nd:YLF/KGW Raman laser operating at near-IR, yellow and lime-green wavelengths

Abstract

A Nd:YLF/KGW Raman laser has been investigated in this work. We have demonstrated CW output powers at six different wavelengths, 1147 nm (0.70 W), 1163 nm (0.95 W), 549 nm (0.65 W), 552 nm (1.90 W), 573 nm (0.60 W) and 581 nm (1.10 W), with higher peak powers achieved under quasi-CW operation. Raman conversion of the 1053 nm fundamental emission is reported for the first time, enabling two new wavelengths in crystalline Raman lasers, 549 nm and 552 nm. The weak thermal lensing associated with Nd:YLF has enabled to achieve good beam quality, M(2) ≤ 2.0, and stable operation in relatively long cavities.

Continuous-Wave Nd:YVO_4 self-Raman lasers operating at 1109nm, 1158nm and 1231nm

“…This extended coverage benefits many applications especially when SRS is used in conjunction with Second Harmonic Generation (SHG) or Sum Frequency Generation (SFG) impacting medicine (retinal laser photocoagulation) [3], laser projection displays, and remote sensing (bathymetry or underwater detection) [4]. All-solid-state continuous-wave (CW) Raman lasers are widely recognized as a practical and efficient way to produce laser outputs in the near infrared, visible and ultraviolet wavebands [5][6][7][8][9][10][11]. Typically, intracavity Raman lasers feature a separate Raman active crystal inserted inside a laser resonator.…”

Intracavity frequency converted Raman laser producing 10 deep blue to cyan emission lines with up to 094 W output power

“…The SHG of the fundamental field delivered a maximum qcw output power of 1.08 W. Cw Raman laser operation is demonstrated, providing 27 mW of output power at 990 nm and weak (<1 mW) irregularly-pulsed blue laser emission at 474 nm. The cw laser performance shows that the quasi-three-level operation is heavily challenged by the induced heat when compared to earlier reported Watt level cw results in the yellow lime green region, using a similar laser cavity based on the four-level transition of the Nd:YLF [6]. Further studies are required to determine whether it is feasible to extract cw blue laser output from this laser system.…”

“…By making use of a high-Q cavity, the highly enhanced intracavity fundamental field provides strong stimulated Raman scattering (SRS), allowing continuous wave (cw) SRS laser operation [3]. In addition, intracavity sum frequency generation (SFG) and second harmonic generation (SHG) have been reported, resulting in laser output in the yellow-orangered spectral region [4][5][6]. Continuous improvements in crystal quality and coating technologies have been of paramount importance for providing optical to optical (diode pump to visible) efficiencies in excess of 20% [4].…”

Broad expansion of optical frequency combs by self-Raman scattering in coupled-cavity self-mode-locked monolithic lasers

“…Consequently, these laser crystals can be employed to generate the so-called self-Raman frequency conversion via stimulated Raman scattering (SRS) [21][22][23][24][25]. Figure 1(a) shows the spontaneous Raman spectrum of KGW crystal (Micro Raman Identify / ProTrusTech Co., Ltd), in which two strong Raman modes at 901 and 768 cm −1 are often used to obtain the Stokes wave with large frequency shifts [26][27][28]. In addition to these two Raman modes, the self-Raman laser at the lowest frequency mode near 89 cm −1 has been successfully demonstrated in recent years [29][30][31].…”