Method for forming heterogeneous single garnet based crystals for passive Q-switched lasers and microlasers

Patent metadata

Field	Value
Publication number	US-9506166-B1
Application number	US-201414332672-A
Country	US
Kind code	B1
Filing date	Jul 16, 2014
Priority date	Jul 8, 2010
Publication date	Nov 29, 2016
Grant date	Nov 29, 2016

Abstract

Disclosed are heterogeneous crystals for use in a laser cavity and methods of forming the crystals. A crystal can be a monolithic crystal containing a garnet-based activator region and a garnet-based Q-switch. Disclosed methods include hydrothermal growth techniques for the growth of differing epitaxial layers on a host. A YAG host material can be doped in one region with a suitable activator ion for lasing and can be formed with another region that is doped with a saturable absorber to form the Q-switch. Regions can be formed with controlled thickness in conjunction. Following formation, a heterogeneous crystal can be cut, polished and coated with mirror films at each end for use in a laser cavity to provide short pulses of high power emissions using high frequency pulse modes.

First claim

What is claimed is:

1. A method for forming a monolithic heterogeneous crystal comprising heating and pressurizing an aqueous solution held within a reactor to develop a temperature differential between a first zone of the reactor and a second zone of the reactor, the reactor containing a garnet forming feedstock in the first zone and a garnet seed crystal in the second zone, the feedstock forming the same garnet as the garnet of the seed crystal, the feedstock including a source for a saturable absorber ion, wherein upon said heating and pressurizing growth of a garnet Q-switch crystal region is initiated on the garnet seed crystal to form a monolithic garnet product crystal, the composition of the Q-switch crystal region differing from the composition of the seed crystal such that the monolithic garnet product crystal is heterogeneous.

2. The method according to claim 1 , the aqueous solution comprising a mineralizer.

3. The method according to claim 1 , wherein the garnet seed crystal is a YAG seed crystal.

4. The method according to claim 1 , the garnet seed crystal comprising an activator ion.

5. The method according to claim 1 , the feedstock further comprising a source for an activator ion.

6. The method according to claim 1 , the feedstock further comprising a source of an ion for balancing lattice charge of the Q-switch crystal region.

7. The method according to claim 1 , wherein the seed crystal is a heterogeneous monolithic crystal.

8. The method according to claim 1 , wherein the seed crystal comprises a region of the garnet that is undoped.

9. The method according to claim 1 , wherein the reactor is lined with an inert noble metal.

10. The method according to claim 1 , wherein the aqueous solution is pressurized to a pressure of between about 5 kpsi and about 30 kpsi.

11. The method according to claim 1 , wherein the temperature of the second zone is between about 450° C. and about 650° C.

12. The method according to claim 1 , wherein the temperature difference is between about 20° C. and about 100° C.

13. The method according to claim 1 , further comprising cutting and polishing the monolithic heterogeneous product to form a smaller heterogeneous monolithic crystal.

14. The method according to claim 1 , further comprising forming a new crystal region on the Q-switch region, the new crystal region differing in composition from the Q-switch region.

15. The method according to claim 14 , wherein the new crystal region is a region of the garnet that is undoped.

16. The method according to claim 14 , wherein the new crystal region is formed according to a method comprising heating and pressurizing an aqueous solution held within a second reactor to develop a temperature differential between a first zone of the second reactor and a second zone of the second reactor, the second reactor containing a garnet forming feedstock in the first zone, this garnet forming feedstock forming the same garnet as the garnet of the monolithic garnet product crystal, the second reactor containing the garnet product crystal in the second zone, wherein upon said heating and pressurizing growth of the new crystal region is initiated on the garnet product crystal.

17. The method according to claim 1 , wherein the saturable absorber ion is included in the feedstock in a concentration between about 0.01 at. % and about 10 at. %.

Assignees

• Univ Clemson
• Clemson Univ Res Found

Inventors

• Kolis Joseph W
• Mcmillen Colin D
• Mann J Matthew

Classifications

• H01S3/1643

  YAG · CPC title

• C30B29/28

  with formula A3Me5O12 wherein A is a rare earth metal and Me is Fe, Ga, Sc, Cr, Co or Al, e.g. garnets · CPC title

• C01F17/34

  Aluminates, e.g. YAlO3 or Y3-xGdxAl5O12 · CPC title

• C30B7/10 Primary

  by application of pressure, e.g. hydrothermal processes · CPC title

• H01S3/0612

  Non-homogeneous structure (H01S3/07 takes precedence) · CPC title