Diamond Raman laser with continuously tunable output from 338 to 380 μm

Abstract

We report a pulsed mid-infrared diamond Raman laser with output tuned from 3.38 to 3.80 μm through varying the optical parametric oscillator (OPO) pump wavelength. To our knowledge this is the longest reported wavelength from a solid-state Raman laser. We generated up to 80 μJ with good beam quality and 22% quantum conversion efficiency. Whilst the conversion process itself is efficient, approximately 40% of the generated Stokes light is lost to multiphonon absorption. By introducing a secondary pump beam at the anti-Stokes wavelength to initiate a seed at the Stokes wavelength through Raman resonant four-wave mixing, the laser threshold was reduced by approximately half, and the maximum output increased by 44% to 115 μJ.

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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Optical parametric generation in orientation-patterned gallium phosphide

“…Temperature-dependent loss measurements for the pump polarization along the [100] axis in the OP-GaP crystal have also been performed, for the first time, indicating a drop in transmission from 28.8% at 50ºC to 19.4% at 160ºC. © 2015 Optical Society of America OCIS codes : (190.4360) Nonlinear optics, devices; (190.4400) Nonlinear optics, materials; (190.4410 Mid-infrared (mid-IR) coherent sources based on optical parametric down-conversion are of great significance for a variety of applications such as spectroscopy [1], up-conversion imaging [2] and as pump source for other nonlinear processes [3]. Oxide-based nonlinear crystals, and especially their quasi-phase matched (QPM) counterparts such as MgO-doped periodically-poled LiNbO3 (MgO:PPLN), stoichiometric LiTaO3 (MgO:sPPLT) and KTiOPO4 (PPKTP), have enabled broadband mid-IR coverage up to ~4 μm, in all time-scales from continuous-wave (CW) to femtosecond domain [4][5][6][7].…”

“…Mid-infrared (mid-IR) coherent sources based on optical parametric down-conversion are of great significance for a variety of applications such as spectroscopy [1], up-conversion imaging [2] and as pump source for other nonlinear processes [3]. Oxide-based nonlinear crystals, and especially their quasi-phase matched (QPM) counterparts such as MgO-doped periodically-poled LiNbO3 (MgO:PPLN), stoichiometric LiTaO3 (MgO:sPPLT) and KTiOPO4 (PPKTP), have enabled broadband mid-IR coverage up to ~4 μm, in all time-scales from continuous-wave (CW) to femtosecond domain [4][5][6][7].…”

Diamond‐based concept for combining beams at very high average powers

“…Diamond also happens to have a high Raman gain coefficient so that in its undoped single crystal form it is a convenient Raman laser medium. To date, a wide range of laser performance has been demonstrated including wavelengths from the ultraviolet to the mid‐infrared , temporal regimes from continuous wave to ultrashort pulses , and average powers up to several hundreds of watts . Its thermal conductivity—the highest of any bulk material at room temperature and more than several hundreds of times higher than most other laser gain materials—in combination with a low thermal expansion coefficient, reveals substantial potential for scaling laser power and brightness.…”