Spectral broadening of a mixed Nd: CYGA crystal with tunable laser operation beyond 1100 nm.

A broader emission band of the novel Nd: CaYGdAlO (Nd: CYGA) mixed crystal was proved by the introduction of Gd ions in Nd: CaYAlO (Nd: CYA) crystal, and a diode-pump tunable Nd: CYGA laser operation was achieved successfully. Due to the broad emission spectrum with the full width at half maximum (FWHM) of 23 nm, a tuning range of 32 nm from 1075 nm to 1107 nm was achieved, and the results were considered to be the first time for Nd-doped crystals to be tuned to such a long wavelength at 1107 nm, which promotes the further development of near-infrared tunable lasers. The maximum output power was 1.05 W at the center wavelength of 1081.4 nm, corresponding to the slope efficiency of 26.6%. Furthermore, we also demonstrated a continuous-wave 1105 nm laser with the output power of 53 mW. Our work indicates that Nd: CYGA crystal is a potential Nd-doped gain medium for generating all-solid-state near-infrared lasers.