Patent ID: 6560253
Filing Date: 2003-05-06
Classification: G02B,H01S

Abstract:
Apparatus for monitoring the wavelength of a beam of laser radiation, comprising:at least one optical filter, said optical filter including a substrate having a filter layer, said filter layer including at least one film layer having a dielectric constant differing from that of said substrate, said optical filter for receiving at least a portion of said beam at a non-zero angle of incidence to a surface of one of said substrate and said filter layer and for producing a first filtered beam in accordance with a first spectral filtering function having a resonant response at a resonant response wavelength; at least one detector for detecting said first filtered beam to produce a first detected signal representative of the intensity of said first filtered beam; and an error circuit in electrical communication with said detector and for producing responsive to said detected signal an error signal representative of the deviation of the wavelength of said beam from a set-point wavelength.