Single crystals with internal doping with laser ions prepared by a hydrothermal method

Patent metadata

Field	Value
Publication number	US-9711928-B2
Application number	US-201313923942-A
Country	US
Kind code	B2
Filing date	Jun 21, 2013
Priority date	Jun 22, 2012
Publication date	Jul 18, 2017
Grant date	Jul 18, 2017

Abstract

Single heterogeneous crystals are described that contain multiple regimes, adjacent regimes varying from one another with regard to function. Also disclosed is a hydrothermal epitaxial growth process that can be utilized to form the single heterogeneous crystals. The single heterogeneous crystals can exhibit enhanced performance when used as a laser gain medium as compared to previously known single crystals and multi-crystal constructs. The heterogeneous single crystal can be utilized for thin disk lasers and can minimize the thermal distortion effects at high powers. The heterogeneous crystal can also serve as an embedded waveguide.

First claim

What is claimed is:

1. A heterogeneous monolithic thin disk laser single crystal comprising:
a first layer, the first layer comprising a host material, the host material being undoped in the first layer;
a second layer, the second layer comprising the host material and a lasing ion dopant; and
a third layer, the third layer comprising the host material, the host material being undoped in the third layer, the second layer being between the first layer and the third layer;
wherein, the heterogeneous monolithic thin disk laser crystal has a face having a diameter of about 1 centimeter or larger, and the second layer has a thickness of between about 30 micrometers and about 150 micrometers.

2. The heterogeneous monolithic thin disk single crystal of claim 1 , further comprising a fourth layer that is immediately adjacent to the second layer, the fourth layer comprising the host material and the lasing ion dopant, wherein the concentration of the lasing ion dopant in the fourth layer differs from the concentration of the lasing ion dopant in the second layer.

3. The heterogeneous monolithic thin disk single crystal of claim 1 , wherein the second layer comprises the lasing ion dopant in a concentration gradient across the thickness of the second layer.

4. The heterogeneous monolithic thin disk single crystal of claim 1 , wherein the refractive index of the first layer and the refractive index of the second layer are matched.

5. The heterogeneous monolithic thin disk single crystal of claim 1 , wherein the second layer further comprises an Lu dopant and/or a Ga dopant.

6. The heterogeneous monolithic thin disk single crystal of claim 1 , wherein the host material is a garnet, a vanadate, a rare earth sesquioxide, a spinel, or a borate.

7. The heterogeneous monolithic thin disk single crystal of claim 1 , wherein the active lasing ion dopant is Nd, Yb, Er, Ho, or Tm.

8. The heterogeneous monolithic thin disk single crystal of claim 1 , wherein the heterogeneous monolithic thin disk crystal has one or more edges, the crystal further comprising a cladding layer on the one or more edges.

9. The heterogeneous monolithic thin disk crystal of claim 8 , the cladding layer comprising an absorber ion that absorbs spontaneously emitted radiation.

10. A method for forming the heterogeneous monolithic thin disk crystal of claim 1 , the method 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 feedstock in the first zone and a seed crystal in the second zone, the seed crystal including the host material, the feedstock including a source for forming the host material and a source for the lasing ion dopant, wherein upon said heating and pressurizing growth of the second layer is initiated on the seed crystal to form an intermediate crystal including the second layer and including the seed crystal as the first layer; and
heating and pressurizing a second 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 second feedstock in the first zone and the intermediate crystal in the second zone, the second feedstock including a source for forming the host material, wherein upon said heating and pressurizing growth of the third layer is initiated on the intermediate crystal, the heterogeneous monolithic thin disk single crystal including the first, second and third layers.

11. The method according to claim 10 , further comprising forming one or more additional layers on the intermediate crystal prior to formation of the third layer on the intermediate crystal, the one or more additional layers including the host material and the lasing ion dopant, the concentration of the lasing ion dopant differing in the one or more additional layers from the concentration of the lasing ion dopant in the second layer, the different concentrations of the lasing ion dopant forming a lasing ion dopant concentration gradient across the heterogeneous monolithic thin disk single crystal.

12. The method according to claim 11 , further comprising heating the heterogeneous monolithic thin disk single crystal to smooth the lasing ion dopant concentration gradient across the one or more additional layers and the second layer.

13. The method according to claim 10 , further comprising forming one or more additional layers on the heterogeneous monolithic thin disk crystal following formation of the third layer.

14. A monolithic single crystal waveguide comprising:
a first layer, the first layer comprising a host material;
a second layer, the second layer comprising the host material and a lasing ion dopant, wherein the active lasing ion dopant consists of Nd, Er, Ho, or Tm, the second layer having a first end and a second end; and
a third layer, the third layer comprising the host material, the host material being undoped in the third layer, the second layer being between the first layer and the third layer, the third layer covering the first end and the second end of the second layer such that the second layer is completely embedded within the first layer and the third layer;
wherein the refractive index of the second layer is different than the refractive index of the first layer and the third layer, the monolithic single crystal waveguide having a length of about 2 centimeters or longer.

15. The monolithic single crystal waveguide of claim 14 , wherein the refractive index of the second layer is larger than the refractive index of the first and the third layer.

16. The monolithic single crystal waveguide of claim 14 , the second layer further comprising an Lu dopant and/or a Ga dopant.

17. The monolithic single crystal waveguide of claim 14 , further comprising a fourth layer, the fourth layer comprising the host material and a lasing ion dopant, the third layer being between the second layer and the fourth layer.

18. The monolithic single crystal waveguide of claim 17 , further comprising a fifth layer, the fifth layer comprising the host material, the host material being undoped in the fifth layer, the fourth layer being between the third layer and the fifth layer.

19. The monolithic single crystal waveguide of claim 14 , further comprising a cladding layer that is external to the first layer and the third layer.

20. The monolithic single crystal waveguide of claim 19 , wherein the cladding layer comprises an ion capable of absorbing a wavelength emitted by the lasing ion dopant.

21. The monolithic single crystal waveguide of claim 14 , wherein the host material is a garnet, a vanadate, a rare earth sesquioxide, a spinel, or a borate.

22. A method for forming the monolithic single crystal waveguide of claim 14 , the method 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 feedstock in the first zone and a seed crystal in the second zone, the seed crystal including the host material, the feedstock including a source for forming the host material and a source for the lasing ion dopant, wherein upon said heating and pressurizing growth of the second layer is initiated on the seed crystal to form an intermediate crystal including the second layer and the seed crystal as the firs

Assignees

• Univ Clemson
• Clemson Univ Res Found

Inventors

• Kolis Joseph
• Mcmillen Colin

Classifications

• H01S3/063

  Waveguide lasers, {i.e. whereby the dimensions of the waveguide are of the order of the light wavelength (waveguide gas lasers H01S3/0315)} · CPC title

• C30B7/10

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

• Y10T428/21

  Circular sheet or circular blank · CPC title

• C30B29/64 Primary

  Flat crystals, e.g. plates, strips or discs · CPC title