An efficient continuous-wave YVO ₄ /Nd:YVO ₄ /YVO ₄ self-Raman laser pumped by a wavelength-locked 878.9 nm laser diode

Abstract

We report an efficient continuous-wave self-Raman laser at 1176 nm based on a 20-mm-long composite YVO 4 /Nd:YVO 4 /YVO 4 crystal and pumped by a wavelength-locked 878.9 nm diode laser. A maximum output power of 5.3 W is achieved at a pump power of 26 W, corresponding to an optical conversion efficiency of 20% and a slope efficiency of 21%. The Raman threshold for the diode pump power was only 0.92 W. The results reveal that in-band pumping by a wavelength-locked diode laser significantly enhances output power and efficiency of self-Raman lasers by virtue of improved pump absorption and relieved thermal loading.

Photon-phonon collaboratively pumped laser

“…It is worthy to note that our PPCP laser does not absorb heat (solid cooling), since those phonon-pumped electrons will finally relax to the ground state by non-radiative transitions, returning heat. Compared to the previous 1176 nm Raman lasers experiencing releasing phonons process that benefits from cooling 38,39 , the hallmark of our PPCP one is the existence of Tth liking heat; thus, they have opposite causality. Such discussion is mainly applicable to the four-level laser systems.…”

Multifunctional Optical Crystals for All-Solid-State Raman Lasers

“…As the most popular multifunctional Raman crystal, the vanadate self-Raman crystals include Nd:YVO 4 [15,16,[20][21][22], Nd:GdVO 4 [18,19,[64][65][66][67][68][69][70][71][72][73][74][75][76][77][78], Yb:YVO 4 [17], and Nd:LuVO 4 [79,80]. Among these self-Raman laser crystals, Nd:YVO 4 has been the most extensively researched and widely employed due to its large Raman gain coefficient, strong absorption of pump radiation over a broad bandwidth, and large emission cross section.…”

“…An efficient AQS eye-safe Raman laser at 1525 nm using a double-end diffusion-bonded Nd:YVO 4 crystal was reported by Chang et al [31] in 2009, and average power of 2.23 W was generated with a conversion efficiency of 13%. In 2016, a high power CW YVO 4 /Nd:YVO 4 /YVO 4 self-Raman laser at 1176 nm, pumped by a wavelength-locked 878.9 nm diode laser, was reported by Fan et al [20], corresponding to maximum output power of 5.3 W and optical conversion efficiency of 20%. To our knowledge, this is the highest power and efficiency among Nd:YVO 4 self-Raman lasers up to now.…”

“…In 2002, Grabtchikov et al [13] demonstrated the first continuous wave (CW) self-Raman laser with Yb:KYW crystal, and the corresponding optical power conversion efficiency was 10%. The vanadate YVO 4 and GdVO 4 were later predicted to be excellent materials for SRS [14], and many vanadate self-Raman lasers have been gradually reported with high average powers (>5 W) and high conversion efficiencies (>20%) [15][16][17][18][19][20]. Moreover, the inclusion of second-harmonic generation (SHG) or sum-frequency generation (SFG) crystals has been verified to be an effective approach for yellow-orange-red generation with average output power up to 8.8 W and diode-visible power conversion efficiency of >30% [21].…”

Efficient Nd:YVO4-KGW intracavity Raman lasers with linear and folded fundamental laser cavities

“…Due to the relatively low χ (3) nonlinear gain, the Raman lasers usually suffer a high SRS threshold of 20 W level when operating in the continuous-wave (CW) regime [5,6]. An alternative approach for efficient CW Raman output is the intracavity pumping scheme, in which the Raman crystals are located inside the cavity of the fundamental laser so that the high circulating power in the fundamental cavity would produce a sufficient gain for CW SRS with watt-level primary laser diode (LD) pump power [7][8][9]. However, the intracavity Raman lasers involve more complex thermal issues, since both processes of lasing and SRS would bring thermal load in the gain media.…”