Optical System with Optical Parametric Oscillator

Abstract

An optical system and method that use a pump laser, an optical parametric oscillator, and two second harmonic generators to generate three colors of laser light. A recirculating optical sub-system includes a gain-guided optical parametric oscillator and one of the second harmonic generators and has four lenses that form two collimated optical beams between the optical parametric oscillator and the second harmonic generator.

What is claimed is: 
     
         1 . An optical system comprising:
 an optical parametric oscillator (OPO);   a second-harmonic generator (SHG);   a first lens which passes light between the OPO and the SHG;   a second lens which passes light between the OPO and the SHG; and   a third lens which passes light between the OPO and the SHG.   
     
     
         2 . The system of  claim 1  further comprising:
 a fourth lens which passes light between the OPO and the SHG. 
 
     
     
         3 . The system of  claim 2  wherein the first lens passes a collimated beam segment to the second lens. 
     
     
         4 . The system of  claim 3  wherein the third lens passes a collimated beam segment to the fourth lens. 
     
     
         5 . The system of  claim 4  wherein the first lens, the second lens, the third lens, and the fourth lens are arranged to form beam segments with a non-rectilinear shape. 
     
     
         6 . The system of  claim 4  further comprising:
 a recirculating optical subsystem; 
 wherein the recirculating optical subsystem focuses a beam waist in the OPO to a same location for 10 circuits around the recirculating optical subsystem with a variation less than 10% of a width of the beam waist. 
 
     
     
         7 . The system of  claim 1  further comprising:
 a first short wave pass (SWP) filter; 
 a second SWP filter; 
 a mirror; and 
 a third SWP filter; 
 wherein the first SWP filter, the second SWP filter, the minor, and the third SWP filter are arranged to form a recirculating optical subsystem. 
 
     
     
         8 . The system of  claim 7  wherein the first SWP filter and the second SWP filter are mounted in an optical module with the OPO; and wherein the minor and the third optical SWP filter are mounted in an optical module with the SHG. 
     
     
         9 . The system of  claim 1  wherein the optical system generates a first infrared beam with a first infrared wavelength and a second infrared beam with a second infrared wavelength. 
     
     
         10 . The system of  claim 9  wherein the first infrared beam is frequency doubled to make a first visible beam with a first visible wavelength and the second infrared beam is frequency doubled to make a second visible beam with a second visible wavelength. 
     
     
         11 . The system of  claim 10  wherein the first visible wavelength is in the range of 430 nm to 480 nm and the second visible wavelength is in the range of 600 nm to 680 nm. 
     
     
         12 . The system of  claim 11  wherein the first visible wavelength is 452 nm and the second visible wavelength 621 nm. 
     
     
         13 . The system of  claim 1  wherein the OPO is pumped by a beam with a wavelength in the range of 510 nm to 550 nm. 
     
     
         14 . The system of  claim 13  wherein the wavelength is 523.5 nm. 
     
     
         15 . The system of  claim 13  wherein the wavelength is 540 nm. 
     
     
         16 . An optical system comprising:
 a first short wave pass (SWP) filter;   an optical parametric oscillator (OPO);   a second SWP filter;   a first lens;   a second lens;   a mirror;   a second-harmonic generator (SHG);   a third SWP filter;   a third lens; and   a fourth lens;   wherein the OPO passes light from the first SWP filter to the second SWP filter, the second SWP filter passes light from the OPO to the first lens, the first lens passes light from the second SWP filter to the second lens, the second lens passes light from the first lens to the mirror, the mirror passes light from the second lens to the SHG, the SHG passes light from the mirror to the third SWP, the third SWP passes light from the SHG to the third lens, the third lens passes light from the third SWP to the fourth lens, the fourth lens passes light from the third lens to the first SWP filter, and the first SWP filter passes light from the fourth lens to the OPO.   
     
     
         17 . A method of generating light comprising:
 focusing a pump beam into an optical parametric oscillator (OPO);   forming an idler beam in the OPO;   focusing the idler beam through a first lens and a second lens into a first second-harmonic generator (SHG); and   recirculating the idler beam through a third lens and a fourth lens back into the OPO.   
     
     
         18 . The method of  claim 17  wherein a beam segment between the first lens and the second lens is collimated; and wherein a beam segment between the third lens and the fourth lens is collimated. 
     
     
         19 . The method of  claim 17  further comprising:
 forming a signal beam in the OPO; 
 separating the idler beam from the signal beam and the pump beam; 
 forming a first second-harmonic beam from the idler beam in the first SHG; and 
 separating and outputting the first second-harmonic beam. 
 
     
     
         20 . The method of  claim 19  further comprising:
 separating and outputting a remaining pump beam; 
 focusing the signal beam into a second SHG; 
 forming a second second-harmonic beam in the second SHG; 
 separating and outputting the second second-harmonic beam; and 
 dumping a remaining signal beam.