SELF-SCANNING TYPE SEMICONDUCTOR LASER

PURPOSE:To provide a semiconductor laser beam source itself with the functions of beam deflection and scanning by changing the oscillation direction of a laser to direct it toward and arbitrary direction by displacing the installed direction of a resonator. CONSTITUTION:On a ultrasonic crystal 11, electrodes for ultrasonic excitation are arranged in positions 131-13n and the symmetrical positions 131'-13n' regarding a laser amplification medium 12. For example, when ultrasonic waves are projected from a pair of electrodes 13k and 13k' toward the laser medium, interference fringes due to the two ultrasonic waves are produced on the laser medium 12 and a diffraction grating due to parallel interference fringes whose period is 1/2 the wavelength of the ultrasonic is formed. The direction of stripes of said diffraction grating is orthogonal to the line connecting the electrodes and a refractive index in the diffraction grating changes synchronously with its period. As laser oscillation is to be generated in the laser medium 12, the control of longitudinal mode is effected by the intervals of the diffraction grating which is formed also in the laser medium by leaking the ultrasonic waves excited in the ultrasonic crystal into the laser medium.