Beam reverser module and optical power amplifier having such a beam reverser module

Patent metadata

Field	Value
Publication number	US-10777958-B2
Application number	US-201715830373-A
Country	US
Kind code	B2
Filing date	Dec 4, 2017
Priority date	Feb 8, 2013
Publication date	Sep 15, 2020
Grant date	Sep 15, 2020

Abstract

A beam reverser module for an optical power amplifier of a laser arrangement comprises at least one reflecting surface for receiving an incoming laser beam propagating in a first direction and reflecting the incoming laser beam into a second direction different from the first direction, wherein the at least one reflecting surface is a highly reflecting surface of at least one mirror.

First claim

The invention claimed is:

1. A module, comprising:
a prism comprising an entrance surface, a first total internal reflection surface, a second total internal reflection surface, and an exit surface; and
a purge device configured to directly purge the prism with a purge rate that varies over a surface of the prism in accordance with a position of the laser beam on or in the prism,
wherein the module is configured so that, during use of the module in an optical power amplifier of a laser arrangement:
a laser beam enters the prism via the entrance surface;
the first total internal reflection surface receives the laser beam entering the prism;
the second total internal reflection surface receives the laser beam reflected at the first total internal reflection surface;
the first and second internal reflection surfaces define an angle greater than 60° with one another;
after reflecting at the second internal reflection surface, the laser beam emerges from the prism via the exit surface; and
the entrance surface is configured so that an angle of incidence of the laser beam as it impinges on the entrance surface is greater than the Brewster angle.

2. The module of claim 1 , wherein the first and second total internal reflection surfaces comprise protection coatings configured to change an electric field of the laser beam on these surfaces to reduce surface absorption of the laser beam.

3. The module of claim 1 , wherein the prism comprises CaF 2 having a linear laser induced absorption coefficient of less than than 0.2×10 −4 cm/mJ.

4. The module of claim 1 , wherein the first and second total internal reflection surfaces comprise protection coatings configured to change an electric field of the laser beam on these surfaces to reduce surface absorption of the laser beam, the prism comprises CaF 2 having a linear laser induced absorption coefficient of less than than 0.2×10 −4 cm/mJ.

5. The module of claim 1 , wherein the entrance surface comprises a high laser durability anti-reflective coating.

6. The module of claim 5 , wherein the exit surface comprises a high laser durability anti-reflective coating.

7. The module of claim 1 , wherein the exit surface comprises a high laser durability anti-reflective coating.

8. The module of claim 1 , wherein:
the first and second total internal reflection surfaces comprise protection coatings configured to change an electric field of the laser beam on these surfaces to reduce surface absorption of the laser beam; and
the entrance surface comprises a high laser durability anti-reflective coating.

9. The module of claim 8 , wherein the exit surface comprises a high laser durability anti-reflective coating.

10. The module of claim 1 , wherein:
the first and second total internal reflection surfaces comprise protection coatings configured to change an electric field of the laser beam on these surfaces to reduce surface absorption of the laser beam; and
the exit surface comprises a high laser durability anti-reflective coating.

11. The module of claim 1 , wherein:
the prism comprises CaF 2 having a linear laser induced absorption coefficient of less than than 0.2×10 −4 cm/mJ; and
the entrance surface comprises a high laser durability anti-reflective coating.

12. The module of claim 11 , wherein the exit surface comprises a high laser durability anti-reflective coating.

13. The module of claim 1 , wherein:
the prism comprises CaF 2 having a linear laser induced absorption coefficient of less than than 0.2×10 −4 cm/mJ; and
the exit surface comprises a high laser durability anti-reflective coating.

14. The module of claim 1 , wherein the purge device is configured to purge the first total internal reflection surface.

15. An amplifier, comprising:
a beam reverser module comprising a prism comprising an entrance surface, a first total internal reflection surface, a second total internal reflection surface, and an exit surface;
a purge device configured to directly purge the prism with a purge rate that varies over a surface of the prism in accordance with a position of the laser beam on or in the prism;
a power amplifier chamber; and
an optical unit,
wherein the module is configured so that, during use of the module in the amplifier:
a laser beam enters the prism via the entrance surface;
the first total internal reflection surface receives the laser beam entering the prism;
the second total internal reflection surface receives the laser beam reflected at the first total internal reflection surface;
the first and second internal reflection surfaces define an angle greater than 60° with one another;
after reflecting at the second internal reflection surface, the laser beam emerges from the prism via the exit surface; and

the entrance surface is configured so that an angle of incidence of the laser beam as it impinges on the entrance surface is greater than the Brewster angle.

16. The amplifier of claim 15 , wherein the first and second total internal reflection surfaces comprise protection coatings configured to change an electric field of the laser beam on these surfaces to reduce surface absorption of the laser beam.

17. The amplifier of claim 15 , wherein the prism comprises CaF 2 having a linear laser induced absorption coefficient of less than 0.2×10 −4 cm/mJ.

18. The amplifier of claim 15 , wherein the purge device is configured to purge the first total internal reflection surface.

Assignees

• Zeiss Carl Smt Gmbh

Inventors

• Schall Michael
• Kraus Johannes
• Muenz Holger
• Schuster Ingrid
• Anderl Willi
• Weber Ulrich
• Bauer Markus
• Erxmeyer Jeffrey
• Le Maire Michel

Classifications

• G02B7/1815 Primary

  with cooling or heating systems (cooling arrangements for laser mirrors H01S3/0401) · CPC title

• H01S3/10023

  by functional association of additional optical elements, e.g. filters, gratings, reflectors · CPC title

• G02B5/04

  Prisms · CPC title

• G02B5/12

  Reflex reflectors · CPC title

• H01S3/225

  comprising an excimer or exciplex · CPC title