# US 5,345,457 A · Dual wavelength laser system with intracavity sum frequency mixing

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- Number: US 5,345,457 A
- Document ID: US5345457A
- Status: Granted
- Kind: A
- Application number: 08/137,947
- Filed: 1993-10-15
- Granted: 1994-09-06
- Earliest claimed: 1993-02-02
- Assignees: Schwartz Electro-Optics, Inc.
- Inventors: Henry H. Zenzie; Peter F. Moulton
- Web page: https://patentgrep.com/patent/US5345457A

## CPC

- H01S 3/108: using non-linear optical devices, e.g. exhibiting Brillouin or Raman scattering {(mode locking using a non-linear element H01S3/1112)}
- H01S 3/07: consisting of a plurality of parts, e.g. segments (H01S3/067 takes precedence)
- H01S 3/0809: {Two-wavelenghth emission}
- H01S 3/0811: {incorporating a dispersive element, e.g. a prism for wavelength selection}
- H01S 3/082: defining a plurality of resonators, e.g. for mode selection or suppression
- H01S: DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL

## Abstract

A dual-wavelength laser system with intracavity, sum-frequency mixing including a bifurcated resonant cavity having a first arm, a second arm and a common arm; a first laser element located in the first arm for providing a first input laser beam of a first wavelength; a second laser element located in the second arm for providing a second input laser beam of a second wavelength; a nonlinear-mixing element in the common arm; and a beam combining device for combining the first and second beams and submitting them to the nonlinear-mixing element for providing an output laser beam of a third wavelength whose energy is the sum of the energy of the input laser beams.

## Claims

### Claim 1

A dual-wavelength laser system with intracavity, sum-frequency mixing comprising:
a bifurcated resonant cavity having a first arm, a second arm and a common arm;
a first laser element located in said first arm for producing a first laser beam of a first wavelength;
a second laser element located in said second arm for producing a second input laser beam of a second wavelength;
a nonlinear-mixing element in said common arm; and
a beam combining device for combining said first and second beams and submitting them to said nonlinear-mixing element for producing an output laser beam of a third wavelength whose energy is the sum of the energy of the input laser beams.

### Claim 2 (depends on 1)

The dual-wavelength laser system of claim 1 in which said first laser element is a solid state element.

### Claim 3 (depends on 1)

The dual-wavelength laser system of claim 1 in which said second laser element is a solid state element.

### Claim 4 (depends on 1)

The dual-wavelength laser system of claim 1 in which said first and second laser elements are the same material.

### Claim 5 (depends on 1)

The dual-wavelength laser system of claim 1 in which each of said laser elements includes a pumping device.

### Claim 6 (depends on 5)

The dual-wavelength laser system of claim 5 in which each said pumping device is a flashlamp.

### Claim 7 (depends on 1)

The dual-wavelength laser system of claim 1 in which said first and second laser elements include infrared lasers.

### Claim 8 (depends on 7)

The dual-wavelength laser system of claim 7 in which said first wavelength is 1064 nm and said second wavelength is 1318 nm.

### Claim 9 (depends on 1)

The dual-wavelength laser system of claim 1 in which said nonlinear-mixing element is potassium titanyl phosphate (KTP).

### Claim 10 (depends on 1)

The dual-wavelength laser system of claim 1 in which said nonlinear-mixing element is lithium niobate (LiNbO.sub.3).

### Claim 11 (depends on 1)

The dual-wavelength laser system of claim 1 in which said nonlinear-mixing element is lithium triborate (LBO).

### Claim 12 (depends on 1)

The dual-wavelength laser system of claim 1 in which said beam combining device includes a Brewster prism assembly.

### Claim 13 (depends on 1)

The dual-wavelength laser system of claim 1 in which said beam combining device includes a dichroic mirror.

### Claim 14 (depends on 1)

The dual-wavelength laser system of claim 1 in which said first and second beams are orthogonally polarized and said beam combining device is a polarizer element.

### Claim 15 (depends on 14)

The dual-wavelength laser system of claim 14 in which said first wavelength is approximately 1064 nm.

### Claim 16 (depends on 14)

The dual-wavelength laser system of claim 14 in which said second wavelength is approximately 1318 nm.

### Claim 17 (depends on 14)

The dual-wavelength laser system of claim 14 in which said third wavelength is approximately 589 nm.

### Claim 18

A dual-wavelength infrared laser system with intracavity, sum-frequency mixing for yellow light generation for vascular lesion removal, comprising:
a bifurcated resonant cavity having a first arm, a second arm and a common arm;
a first solid state H2 pfm infrared laser element located in said first arm for producing a first laser beam at approximately 1 micron;
a second solid state H2 pfm infrared laser element located in said second arm for producing a second input laser beam at approximately 1.3 microns;
a nonlinear-mixing element in said common arm; and
a beam combining device for combining said first and second beams and submitting them to said nonlinear-mixing element for producing an output laser beam of a yellow wavelength whose energy is the sum of the energy of the input laser beams.