Polarization preserving reflector and method
First Claim
1. A laser system for machining a work piece comprising:
- a laser source for generating a beam of linearly polarized radiation;
means for focusing the radiation onto the surface of a work piece; and
delivery means for transmitting the radiation beam from the laser source to the focusing means, said delivery means including quarter wave optical element for converting the linearly polarized beam into a circularly polarized beam, said delivery means further including at least one polarization preserving reflecting element having an average reflectance of at least 99.5 percent of the incoming radiation beam, said polarization preserving reflecting element for maintaining the polarization state of the incoming radiation beam through varying angles of incidence such that the phase shift induced by said polarization preserving reflecting element is less than 2.5 degrees from zero for angles of incidence between zero and 75 degrees whereby the polarization state of the beam delivered to the focusing means will be substantially circular thereby preserving the quality of the machining operation.
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0 Petitions
Accused Products
Abstract
A polarization preserving reflector for reflecting an incident beam of monochromatic radiation, said beam having a polarization configuration and an angle of incidence. The polarization preserving reflector comprises a substrate; a highly reflective layer positioned adjacent to said substrate; and at least two thin film optical layers one of which being positioned adjacent to the highly reflective layer, one of the thin film optical layers having a high refractive index and another having a low refractive index, for maintaining the incident polarization configuration while producing a high reflectance upon reflection of the beam therefrom in a wide range of the angle of incidence from approximately zero degrees to 75 degrees.
60 Citations
13 Claims
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1. A laser system for machining a work piece comprising:
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a laser source for generating a beam of linearly polarized radiation; means for focusing the radiation onto the surface of a work piece; and delivery means for transmitting the radiation beam from the laser source to the focusing means, said delivery means including quarter wave optical element for converting the linearly polarized beam into a circularly polarized beam, said delivery means further including at least one polarization preserving reflecting element having an average reflectance of at least 99.5 percent of the incoming radiation beam, said polarization preserving reflecting element for maintaining the polarization state of the incoming radiation beam through varying angles of incidence such that the phase shift induced by said polarization preserving reflecting element is less than 2.5 degrees from zero for angles of incidence between zero and 75 degrees whereby the polarization state of the beam delivered to the focusing means will be substantially circular thereby preserving the quality of the machining operation. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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Specification