Efficient conversion of a 1064 μm Nd:YAG laser to the eye-safe region using a diamond Raman laser

Abstract

We report an efficient 1.485 μm external cavity diamond Raman laser operating on the 2nd Stokes shift of a 1.064 μm Nd:YAG pump laser. 1.63 W pulsed at 5 kHz is produced with a quantum conversion efficiency of 71% and excellent beam quality. Numerical modelling confirms that optimal operation is achieved with low output coupling reflectivity.

Diamond Nanophotonics

“…Diamond offers an advantage in this regard, as diamond's large Raman shift of 1332 cm -1 allows the eye-safe region to be reached from 1.064 µm (a very common pump laser wavelength) in 2 shifts instead of 3, which reduces the complexity of mirror coatings and increases the efficiency. Using a small diamond crystal, 2 nd order Stokes conversionto 1.485 µm was demonstrated with conversion efficiencies exceeding 70% [145] . Using an externalcavity, and diamond as a Raman crystal, output powers of up to 14.5 W were achieved at wavelengths of 1240 nm and 1485 nm using a using a 1064 nm pump laser.…”

On-chip diamond Raman laser

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Synthetic single-crystal diamond has recently emerged as a promising platform for Raman lasers at exotic wavelengths due to its giant Raman shift, large transparency window and excellent thermal properties yielding a greatly enhanced figure-of-merit compared to conventional materials [1, 2, 3]. To date, diamond Raman lasers have been realized using bulk plates placed inside macroscopic cavities [3,4,5,6,7,8,9,10,11,12,13], requiring careful alignment and resulting in high threshold powers (~W-kW). Here we demonstrate an on-chip Raman laser based on fully-integrated, high quality-factor, diamond racetrack microresonators embedded in silica.

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Sub-100 ps Monolithic Diamond Raman Laser Emitting at 573 nm

“…The fitting parameters in the modeling were the effective Raman gain (geff) and a dimensionless spontaneous scattering factor (ksp) for the 1st and 2nd Stokes. Effective Raman gain is determined by the overlap factor between the pump and the Raman modes, and by the linewidth of the pump emission [12,18]. The results of the modelling presented in Figs.…”