METHOD AND APPARATUS FOR DETECTING THE WAVELENGTH OF A LASER BEAM.

摘要

A method and an apparatus for detecting the wavelength of a laser beam by utilizing an optogalvano effect based upon atoms or molecules in the plasma. Atoms or molecules in the plasma are irradiated with a laser beam. The impedance of the plasma at this moment is detected to determine whether the wavelength of the laser beam is in agreement with a predetermined absolute wavelength. The result of detection is used for controlling the wavelength of the laser beam. ABSTRACT A method and apparatus for sensing the wavelength of a laser beam using an optogalvano effect by atoms or molecules in plasma. Atoms or molecules in the plasma are irradiated with the laser beam. The impedance of the plasma at that time is sensed to sense whether the wavelength of the laser beam coincides with a predetermined absolute wavelength. The sensed result is use to control the wavelength of the laser beam.