Compact Cr:ZnS channel waveguide laser operating at 2333 nm

Abstract

A compact mid-infrared channel waveguide laser is demonstrated in Cr:ZnS with a view to power scaling chromium laser technology utilizing the thermo-mechanical advantages of Cr:ZnS over alternative transition metal doped II-VI semiconductor laser materials. The laser provided a maximum power of 101 mW of CW output at 2333 nm limited only by the available pump power. A maximum slope efficiency of 20% was demonstrated.

Towards Mid-IR Waveguide Lasers: Transition Metal Doped ZnS Thin Films

“…Raman features between 280 and 340 (Fig 2a) indicate substitutional incorporation of the ions into the lattice. For iron, little degradation of the Raman spectrum was observed even at 4% concentration, in accord with the absorption results, and a large  (3) at 7% suggests these films may function as saturable absorbers. By 9%, Raman and  (3) results both indicate the onset of considerable lattice disruption (Fig 2a,b).…”

“…For iron, little degradation of the Raman spectrum was observed even at 4% concentration, in accord with the absorption results, and a large  (3) at 7% suggests these films may function as saturable absorbers. By 9%, Raman and  (3) results both indicate the onset of considerable lattice disruption (Fig 2a,b). X-Ray data (Fig 2c) show increasing order upon small additions of TM ions, with a significant reduction in the full-width half maximum of the primary diffraction peak (wurtzite (002)/sphaelerite (111)) for concentrations up to 2% for Cr and up to 7% for Fe, in agreement with Raman data.…”

“…One of the present limitations to the wide scale deployment of systems in this wavelength range is the size and cost of the sources, which are based on bulk gain materials [1,2]. Fabrication of waveguide lasers is desirable, but to date the best results have been obtained by defining a waveguide within a bulk material [3]. Polycrystalline and ceramic [4][5][6] materials have been used successfully for lasing, which suggests that thin film materials of sufficient quality for the production of channel waveguide devices are possible, and some progress has been made with pulsed laser deposition and molecular beam evaporation of TM doped films [7,8].…”

Laser Active Materials for High-Intensity Lasers

“…Added to the fact that these Cr-doped chalcogenides have been already (or can be) prepared in the form of waveguides, by using different techniques such as RF magnetron-sputtering [59], pulsed laser deposition [60] and LPE [16], and also in the form of "thin" disks [61] by using the top-down technique (fine cutting and polishing of bulk crystals and ceramics), thus in much better conditions for an efficient management (standard or cryogenic cooling) of the thermal loads, these laser materials have the potential to be power scaled up to much higher intensities than that already obtained [62].…”

Nonlinear optical response and structural properties of MBE-grown Fe:ZnS films

“…Cr 2+ doped ceramic ZnS has been successfully used for lasers in the 2-4 µm band [8]. Initially, confinement was provided by using femtosecond processing to define the boundaries of a waveguide [9,10] within a bulk sample, but new studies [11,12] suggest that vacuum-deposited thin films may be suitable for fabrication of waveguide or disk lasers. Moreover, MBE-grown Cr:ZnS thin films show promise as saturable absorbers for 1.5 µm erbium lasers [13].…”