Patent ID: 7515625

Claim:
A laser apparatus using a multipath solid-state slab laser rod that has a trapezoid or parallelogram-shaped cross section by a plane including an optical path in the slab and that has a light amplifying effect, comprising: a solid-state slab laser rod that is able to amplify incident light and has an end face A, an end face B which faces the end face A, two parallel side faces C and D , adjacent to the end faces A and B and slab top and slab bottom faces E and F providing a light propagation path between the end faces A and B through one or more reflections on the side faces, and an excitation light source that excites the solid-state slab laser rod from any of the six faces A through F, wherein the light that is incident through the end face A: (1) is reflected at the side face C or the side face D one or more times to propagate towards the end face B, (2) is reflected at the end face B by total internal reflection with an incidence angle greater than the critical angle of the slab medium, (3) is reflected at the side face C or the side face D one or more times to propagate back to end face A, and (4) is reflected at the end face A by the total internal reflection with an incidence angle greater than the critical angle, successively, and after repeating this light propagation through (1) to (4) one or more times, the propagating light is reflected at the side face C or the side face D one or more times to reach towards the end face B and falls on the end face B with an incidence angle less than the critical angle to be refracted out from the end face B, as amplified light.