Broadly tunable two-color lasing of Cr:LiCAF with on-surface and off-surface optical axis birefringent filters: performance comparison.

Abstract

We studied the two-color lasing performance of a Cr:LiCAF laser using crystal quartz on-surface and off-surface optical axis birefringent filters (BRFs). Four different on-surface optical axis BRFs with thicknesses of 2mm, 4mm, 8mm, and 16mm, and three different off-surface optical axis BRFs with a diving angle of 25° and thicknesses of 2mm, 4mm, and 8mm have been tested. Two-color lasing operation could be achieved in tens of different pairs of wavelengths using both types of BRFs. Regular on-surface optical axis BRFs provided two-color lasing in the 772-810nm interval, with a discretely tunable wavelength separation of 1 to 37nm (0.5 to 17THz). In comparison, the off-surface optical axis BRFs enabled scanning of two-color lasing spectra in a much broader wavelength range between 745nmand850nm with a discretely tunable wavelength separation of 0.8 to 99nm (0.4 to 46THz). The results clearly demonstrate the advantages of using off-surface optical axis BRFs to achieve two-color lasing with broadly tunable wavelength separation.