PURPOSE: To sufficiently ensure the frequency sweeping amount of a laser beam by using a voltage signal having a low voltage value by a method wherein a frequency sweeping means is provided with a plurality of power amplifiers used to apply a plurality of voltage signals to a crystal and the action timing operation of the plurality of power amplifiers is controlled individually by using a timing control means.
CONSTITUTION: Voltage signals Ea to Ec from power amplifiers 32a to 32c which are actuated by a frequency from an oscillator 40 are applied to a crystal 31; a laser beam L1 which is passed through the crystal 31 is phase-modulated by a change in the refractive index of the crystal 31; a frequency is swept. The amplification timing operation of a laser beam L2 by an excitation source 52 for amplification use and by a laser amplification medium 51 is adjusted by a delay circuit 60d. When a plurality of voltage signals Ea to Ec are applied to the crystal 31 at a frequency sweeping means 3OA in this manner, a frequency sweeping amount can be ensured sufficiently by a comparatively low voltage.
IWATA AKIHIKO
TAKEDA YASUTOSHI
ITO HIROSHI
FUKAMI TADASHI
EGURI SHIGEO
