PROBLEM TO BE SOLVED: To provide a phase conjugate mirror for ultrashort pulse light and an optical amplifier using the same.
SOLUTION: The ultrashort pulse light with a waveform A from a laser element is rotated by a polarization beam splitter 2 and a Faraday rotator 3. The ultrashort pulse light passes through a 1st half-wavelength plate 4 and is reflected by a mirror 5, passed through a cylindrical lens 6, and amplified by an amplifier 7 excited by an exciting diode, and then the light passes through a cylindrical lens 8 of a next stage, a 2nd half-wavelength plate 9, and a lens 10, and is incident on the phase conjugate mirror for ultrashort pulse light through a mirror 22, a lens 23, and a mirror 24. Signal light from the mirror 24 is incident on a solid-state medium 11, passes through a 1st lens 12, and is reflected by a mirror 14 and further by a mirror 15, passes through a 2nd lens 13 and impinges on the solid-state medium 11 again, so that the light is projected as a phase conjugate wave. The projected light passes through the same route reversely and is further amplified by the amplifier 7 and rotated by the Faraday rotator 3, and then an output of ultrashort pulse light with a waveform B is obtained from the polarization beam splitter 2.