Patent ID: 7916393

Claim:
A laser application device comprising a laser beam system, wherein the laser beam system comprises: a laser oscillator for outputting, along a same optical axis a first wavelength which is linearly polarized and a second wavelength which is linearly polarized; and an optical level control device that is capable of varying a light transmittance of each of said first wavelength and said second wavelength that are coupled along essentially a same optical axis; wherein said optical level control device comprises: a wavelength-dependent wavelength plate that receives said first wavelength and said second wavelength, said wavelength plate functioning as a half-wave plate with respect to said first wavelength and as a full-wave plate with respect to said second wavelength; and a polarization beam splitter which receives said first wavelength and said second wavelength from said wavelength plate and transmits and reflects said first wavelength and said second wavelength, such that a transmittance of said first wavelength and a transmittance of said second wavelength along essentially a same optical axis are based on the polarization of said first wavelength and said second wavelength.