OPTICAL AMPLIFICATION DEVICE AND OPTICAL AMPLIFICATION METHOD

An optical amplification device 1A includes: a laser medium 2 that amplifies input light L1 to generate output light L2; an excitation light source 3 that supplies excitation light L3 used for amplifying the input light L1, to the laser medium 2; a resonator 4 that includes a pair of first optical elements 6A and 6B disposed to optically face each other with the laser medium 2 interposed between the first optical elements 6A and 6B and that resonates generated light L4 generated in the laser medium 2 through the supply of the excitation light L3; and an optical switch 5 disposed on an optical path of the resonator 4 between the pair of first optical elements 6A and 6B.