Patent ID: 7403554

Claim:
A laser-diode-excited solid-state laser apparatus comprising: a GaN-based compound laser diode which emits an excitation laser beam; and a solid-state laser crystal which is doped with Er 3+ , and emits a solid-state laser beam generated by one of a first transition from 4 S 3/2 to 4 I 15/2 and a second transition from 2 H 9/2 to 4 I 13/2 when the solid-state laser crystal is excited with said excitation laser beam, wherein the solid-state laser crystal produces both the first transition and the second transition when the solid-state laser crystal is excited with said excitation laser beam, and the solid-state laser crystal includes a first coating disposed on a backward end surface of the solid-state laser crystal and a second coating disposed on a forward end surface of the solid-state laser crystal, which enable the solid-state crystal to emit the solid-state laser beam generated by one of the first transition and the second transition.