PURPOSE: To improve measuring precision of a wavelength, by a method wherein a laser beam transmitting plate is located at a given tilt angle to an emitting surface of a laser element between a laser element and a condeser to prevent feedback of a laser beam, reflected by the condenser, to the laser element.
CONSTITUTION: A semiconductor infrared laser element 3 to be measured the oscillating wavelength is located on a cooling base A connected to a cooling rod 5 of a cooler, and is positioned in an insulating container 1 and facing and opposite to a transmission window 2. A condenser 6, spectroscope 7 and an infrared detector 8 are situated on an emitting optical axis of laser beam from the element 3. An infrared transmitting plate 21 is slightly movably situated at a given tilt angle between the window 2 and the condenser 6. Laser beam emitted from the element 3 transmits through the window 2 and the transmitting plate 21 and enters the condenser 6. Meanwhile, a part of laser beam reflected by the condenser 6 is diffused on the surface, positioned facing and opposite to the condenser 6, of the transmitting plate 21, and this prevents the feedback of the laser beam to the laser beam emitting end surface of the element 3 and enables stabilization of the laser beam oscillating motion of the element 3. This permits the improvement of measuring precision of a wavelength.
SHINOHARA KOUJI
KAWABATA YOSHIO
FUKUDA HIROKAZU
YAMAMOTO KOUSAKU
