Reflection/absorption coating for laser slabs

Patent metadata

Field	Value
Publication number	US-9465165-B2
Application number	US-201414318793-A
Country	US
Kind code	B2
Filing date	Jun 30, 2014
Priority date	Jun 30, 2014
Publication date	Oct 11, 2016
Grant date	Oct 11, 2016

Abstract

An optical waveguide for guiding electromagnetic waves. One example of an optical waveguide includes a waveguide substrate, at least one layer of low index optical coating formed on a surface of the waveguide substrate, and a thin layer of metal formed on a surface of the at least one layer of the low index optical coating, where the at least one layer of low index optical coating is disposed between the waveguide substrate and the thin layer of metal. The thin layer of metal can have a thickness in a range of about 5 nm to about 20 nm. In one example, the thin layer of metal is chromium.

First claim

What is claimed is:

1. An optical waveguide, comprising:
a single crystal substrate;
at least one layer of a low index optical coating formed on a surface of the single crystal substrate; and
a thin layer of metal formed on a surface of the at least one layer of the low index optical coating, the thin layer of metal having a thickness in a range of about 5 nm to about 20 nm, and the at least one layer of the low index optical coating disposed between the single crystal substrate and the thin layer of metal.

2. The optical waveguide of claim 1 , wherein the thin layer of metal has a thickness of about 10 nm.

3. The optical waveguide of claim 1 , wherein the thin layer of metal is deposited onto the at least one layer of the low index optical coating.

4. The optical waveguide of claim 1 , wherein the thin layer of metal is chromium.

5. The optical waveguide of claim 1 , further comprising a thermal optical interface in thermal communication with a surface of the thin layer of metal, the thin layer of metal disposed between the at least one layer of the low index optical coating and the thermal optical interface.

6. The optical waveguide of claim 5 , wherein the thermal optical interface is a layer of graphite.

7. The optical waveguide of claim 1 , wherein the thin layer of metal has an extinction coefficient of at least 3 at a wavelength of 1030 nm.

8. The optical waveguide of claim 1 , wherein the at least one layer of the low index optical coating is Al 2 O 3 having a thickness of about 3000 nm.

9. The optical waveguide of claim 1 , wherein the single crystal substrate is a slab of yttrium aluminum garnet (YAG).

10. An optical waveguide apparatus comprising:
an optical waveguide including:
a single crystal substrate;
a layer of low index optical coating formed on a surface of the single crystal substrate; and
a thin layer of metal formed and on a surface of the layer of low index optical coating, the thin layer of metal having a thickness in a range of about 5 nm to about 20 nm, and the layer of low index optical coating disposed between the single crystal substrate and the thin layer of metal; and

at least one light source disposed on a side surface of the single crystal substrate and configured to emit pump light into the single crystal substrate in a direction of a length of the single crystal substrate.

11. The optical waveguide apparatus of claim 10 , wherein the at least one light source emits pump light at a wavelength in a range of about 1000 nm to about 1100 nm.

12. The optical waveguide apparatus of claim 11 , wherein pump light is at a wavelength of about 1030 nm.

13. The optical waveguide apparatus of claim 12 , wherein the at least one light source is configured to emit the pump light at an angle of incidence on the side surface of the single crystal substrate of less than 70 degrees.

14. The optical waveguide apparatus of claim 13 , wherein the thin layer of metal has a reflectivity of less than 40%.

15. The optical waveguide apparatus of claim 14 , wherein the thin layer of metal has an extinction coefficient of at least 3.

16. The optical waveguide apparatus of claim 10 , wherein the thin layer of metal has a thickness of about 10 nm.

17. The optical waveguide apparatus of claim 10 , wherein the thin layer of metal is chromium.

18. The optical waveguide apparatus of claim 10 , further comprising a thermal optical interface in thermal communication with a surface of the thin layer of metal, the thin layer of metal disposed between the at least one layer of the low index optical coating and the thermal optical interface.

Assignees

• Raytheon Co

Inventors

• Murgai Vijay

Classifications

• H01S5/02469

  Passive cooling, e.g. where heat is removed by the housing as a whole or by a heat pipe without any active cooling element like a TEC · CPC title

• G02B2006/12135

  Temperature control · CPC title

• H01S5/2022 Primary

  Absorbing region or layer parallel to the active layer, e.g. to influence transverse modes · CPC title

• H01S5/2027

  Reflecting region or layer, parallel to the active layer, e.g. to modify propagation of the mode in the laser or to influence transverse modes · CPC title

• G02B6/132 Primary

  by deposition of thin films · CPC title