Patent ID: 9509112
Filing Date: 2016-11-29
CPC Classification: G02F,H01S

Claim Text:
1. A deep ultra-violet (DUV) continuous wave (CW) laser comprising: a fundamental CW laser configured to generate a fundamental frequency with a corresponding wavelength between about 1 μm and 1.1 μm; a third harmonic generator module including at least one periodically poled first non-linear optical (NLO) crystal, said third harmonic generator module positioned to receive a first portion of the fundamental frequency and configured to generate a third harmonic; and a fourth harmonic generator module comprising: a plurality of mirrors configured to form a cavity resonant at the corresponding wavelength of the fundamental frequency; a coupler configured to couple a second portion of the fundamental frequency in the cavity such that the second portion is directed along a cavity light path defined by the plurality of mirrors; a second NLO crystal disposed in the cavity light path; one or more lenses configured to focus the third harmonic inside the second NLO crystal such that the third harmonic overlaps the second fundamental portion inside the second NLO crystal, wherein the second NLO crystal is configured to combine said second portion of the fundamental frequency with the third harmonic to generate a fourth harmonic; and a beam splitter configured to reflect an unconsumed portion of the third harmonic leaving the second NLO crystal away from said cavity light path such that said unconsumed third harmonic portion does not recirculate in the cavity.