| 摘要 |
PURPOSE:To stabilize the frequency at the maximum value or at the minimum value of the output-intensity.frequency characteristic curve by thermal modulation of the laser tube length by a method wherein the heater in an internal mirror laser tube coated with a thin film heater is supplied with modulated power. CONSTITUTION:The power modulated at a frequency (f) given by an oscillator 5 is impressed on the thin film heater 2 from a power controller 8. Thereby, the length of the laser tube 1 undergoes modulation, and a beam intensity-modulated according to the output-intensity frequency characteristic curve is outputted from the laser tube 1. Intensity modulation capable of sufficient detection of the region with a frequency (f) up to approx. 1kHz can be given because of good characteristic of heat transfer between the heater 2 and the heat laser tube 1. Part of output light or weak output obtained out of the back of the laser tube 1 are transmitted through a polarizing plate 3. If this output light is emitted out of the transmission-easy polarizing surface of the polarizing plate 3 at only one of the number of vertical mode 1 or 2 of laser beam, the light transmitting through the polarizing plate 3 comes into only a single mode, resulting in the production of better modulated signals. |
