METHOD AND APPARATUS FOR CALIBRATING A LASER WAVELENGTH CONTROL MECHANISM

摘要

Calibration of a wavelength adjustment mechanism (104) of a laser is achieve d using a hollow cathode absorption lamp (114). The lamp is provided with a vaporous material having a precisely known wavelength of maximum absorption. A photo-detector (130) detects the amount of light from the laser beam absorbe d by the vaporous material as a function of wavelength. The wavelength of the laser is adjusted to achieve maximum absorption such that the actual laser beam wavelength may be compared with an expected wavelength to determine a calibration offset. The hollow cathode lamp (114) is operated to produce a vaporous material of known absorption characteristic but is illuminated at a level substantially below a level required for conventional opto-galvanic resonance.