JPS6489383A - Laser beam source - Google Patents

Abstract

PURPOSE:To obtain a variable wavelength laser beam source of narrow spectrum by operating a phase conjugate resonator immediately after driving a laser while forcibly making a pump beam with a mirror, and changing oscillating wavelengths by wavelength selecting means. CONSTITUTION:A beam irradiated from an end surface 11 of a semiconductor laser 1, which passes through a BaTiO3 crystal 2 and is made to be parallel beams by a lens 3, is reflected by a mirror 4. The beam, further passing through a beam isolator 5, only the predetermined wavelength thereof passing through the crystal 2 via a diffraction grating 6, is made to return along this beam path by being reflected by a mirror 7. This reflecting beam becomes a forced pump beam and generates a standing wave between the diffracted beam and itself, whereby a phase conjugate wave is immediately generated against the injected laser beam. The wavelength of the phase conjugate wave is equal to that of the standing wave. When rotating the diffraction grating 6, the wavelength of the standing wave is changed, thereby allowing the oscillating wavelength to be changed. The isolator 5 prevents the reflecting beam by the mirror 7 from going back to the laser 1. An external output laser beam is injected from the opposite surface of the end surface 11 of the semiconductor laser 1. According to the constitution, a laser beam source, which is extremely good in response and thermally and mechanically stable, can be obtained.