Highly efficient picosecond diamond Raman laser at 1240 and 1485 nm

Abstract

We present a highly efficient picosecond diamond Raman laser synchronously-pumped by a 4.8 W mode-locked laser at 1064 nm. A ring cavity was adopted for efficient operation. With a low-Q cavity for first-Stokes 1240 nm, we have achieved 2.75 W output power at 1240 nm with 59% overall conversion efficiency. The slope efficiency tended towards 76% far above the SRS threshold, approaching the SRS quantum limit for diamond. A high-Q first-Stokes cavity was employed for second-Stokes 1485 nm generation through the combined processes of four-wave mixing and single-pass stimulated Raman scattering. Up to 1.0 W of second-stokes at 1485 nm was obtained, corresponding to 21% overall conversion efficiency. The minimum output pulse duration was compressed relative to the 15 ps pump, producing pulses as short as 9 ps for 1240 nm and 6 ps for 1485 nm respectively.

Ultrafast second-Stokes diamond Raman laser

“…There are two previous ultrafast cascaded synchronously-pumped crystalline Raman lasers, each working differently. Second-Stokes output at 1485 nm with 10 ps pulse duration was observed with a maximum of 1 W of second-Stokes average power from 4.8 W pump power from a 1064 nm, 15 ps laser [9]. This corresponds to a 21% conversion efficiency.…”

“…Stimulated Raman scattering (SRS) is an alternative nonlinear optical process that can shift the wavelength of a conventional laser to one or more longer wavelengths. Conversion of picosecond pulsed laser oscillators using SRS in crystals has been demonstrated for first-and second-Stokes output in the visible and infrared [7][8][9]. This has been extended into the femtosecond regime for first-Stokes output, generating pulses as short as 25.5 fs [10][11][12].…”

Diamond Nanophotonics

“…This architecture allowed a selectable method for uni-directional forwards and backwards operation, and efficient 2 nd Stokes generation in a singly resonant cavity. Up to 1.0 W output power was obtained in the eye-safe region at 1485 nm, corresponding to 21% overall conversion efficiency [146] .…”

Ti:sapphire-pumped diamond Raman laser with sub-100-fs pulse duration

“…Synchronously pumped Raman lasers have the potential to efficiently and controllably convert ultrafast pulse trains, even with nanojoule pulse energies [6][7][8][9][10][11][12]. In these lasers, the round-trip time of the pump laser and an external Raman laser cavity are matched, resulting in active-mode-locked operation of the Raman laser output.…”