T-shaped laser pumping device

Patent metadata

Field	Value
Publication number	US-12483000-B2
Application number	US-202117913424-A
Country	US
Kind code	B2
Filing date	Mar 23, 2021
Priority date	Mar 24, 2020
Publication date	Nov 25, 2025
Grant date	Nov 25, 2025

Abstract

A laser pumping assembly includes a parallelepipedal solid laser medium having the shape of a plate in a horizontal plane (xy) and a thickness e L , the laser medium having an absorption spectral band and an associated absorption coefficient α; at least one light emission module intended to pump the laser medium, comprising a fluorescent parallelepipedal crystal called a concentrator, having the shape of a plate of thickness e c′ , the concentrator having at least one illumination face illuminated by electroluminescent radiation and being configured to absorb the electroluminescent radiation and emit fluorescence radiation in a spectral range exhibiting an overlap with the absorption spectral band, the concentrator having an emitting face; the concentrator being in optical contact, via the emitting face, with a receiving face of the laser medium, the concentrator being arranged perpendicular to the laser medium such that the one or more illumination faces are perpendicular to the receiving face so as to perform transverse pumping of the laser medium, the optical contact being designed such that a portion of the fluorescence radiation trapped in the concentrator by total internal reflection is able to pass into the laser medium by passing through the emitting face, and be trapped in the laser medium by total internal reflection, the thickness e l of the laser medium being such that e L ≤L abs /5 where L abs =1/α is an absorption length of the laser medium.

First claim

The invention claimed is:

1 . A laser pumping assembly comprising:
a parallelepipedal solid laser medium (ML) having the shape of a plate in a horizontal plane (xy) and a thickness e L , said laser medium having an absorption spectral band and an associated absorption coefficient α; at least one light emission module (ME) intended to pump the laser medium, comprising: a plurality of light-emitting diodes (LED) configured to emit electroluminescent radiation (L d ) at a wavelength λ d ; a fluorescent parallelepipedal crystal called a concentrator (CL), having the shape of a plate of thickness e c′ , said concentrator having at least one illumination face (SI 1 , SI 2 ) illuminated by said electroluminescent radiation (L d ) and being configured to absorb said electroluminescent radiation (L d ) and emit fluorescence radiation in a spectral range exhibiting an overlap with said absorption spectral band, said concentrator having an emitting face (SE) having dimensions e c ×w c , w c being a width of the concentrator;
said concentrator being in optical contact, via said emitting face (SE), with a receiving face (SR, SR 1 , SR 2 ) of the laser medium, said concentrator being arranged perpendicular to the laser medium such that the one or more illumination faces (SI 1 , SI 2 ) are perpendicular to said receiving face so as to perform transverse pumping of said laser medium,
the optical contact being designed such that a portion (L g ) of said fluorescence radiation trapped in the concentrator (CL) by total internal reflection is able to pass into the laser medium (ML) by passing through said emitting face (SE), and be trapped in the laser medium (ML) by total internal reflection,
said thickness e L of the laser medium being such that e L ≤L abs /10 where L abs =1/α is an absorption length of the laser medium.

2 . The laser pumping assembly as claimed in claim 1 , wherein a ratio between a surface area of the receiving face (SR) of the laser medium and a surface area of the emitting face of the concentrator (SE) is greater than 5, and wherein a ratio between a surface area of the illumination face of the concentrator and a surface area of the emitting face of the concentrator is greater than or equal to 100.

3 . The laser pumping assembly as claimed in claim 1 , comprising at least a first recycling mirror (MR 1 ) coupled to an exit face of the concentrator (FSC) opposite said emitting face and/or a second recycling mirror (MR 2 ) coupled to a face of the laser medium (SR 2 ) opposite said receiving face.

4 . A laser system comprising the laser pumping assembly as claimed in claim 1 and at least two cavity mirrors (M 1 , M 2 ) so as to form a laser cavity wherein the assembly is arranged, a laser beam (FL) propagating in said laser medium in a propagation direction (Dp), passing through two opposing faces, called laser faces (SL), each having dimensions e L ×w L , w L being called transverse dimension, and at least one emission module of the laser pumping assembly performing transverse pumping of the laser medium.

5 . The laser system as claimed in claim 4 , wherein the laser cavity is configured such that a horizontal dimension of the laser beam wp and a vertical dimension w a on each laser face is less than, respectively, half the transverse dimension of the laser face and half the horizontal dimension of the laser face, such that w b ≤w L /2 in the horizontal plane and w a ≤e L /2 in the vertical plane.

6 . The laser system as claimed in claim 5 , wherein the laser cavity is configured such that the propagation direction of the laser beam (Dp) in the laser medium is parallel to the concentrator and such that the laser beam propagates below the concentrator, said width w c of the concentrator being equal to a length L L of the laser medium such that the laser beam is amplified over all of its propagation in the laser medium.

7 . The laser system as claimed in claim 4 , furthermore comprising a first and a second coupling prism (PR 1 , PR 2 ) coupled respectively to a laser face, said prisms being configured to deflect said laser beam such that it is guided by total internal reflection in said laser medium onto the receiving face and a face opposite said receiving face, the cavity being designed such that a vertical dimension of the laser beam w a is such that w a ≤e L sin θ v , where θ v is an angle of incidence of the laser beam on said receiving face.

8 . The laser system as claimed in claim 4 , comprising a plurality of emission modules coupled to the receiving face (SR) of the laser medium.

9 . The laser system as claimed in claim 8 , wherein said plurality consists of a first and a second emission module arranged side-by-side and substantially parallel to one another, said system furthermore comprising an LED-cooling system (CS) arranged between the first and the second emission module, the laser beam propagating parallel to and below the concentrators of the first and the second emission module, such that the laser beam is amplified in a region pumped simultaneously by the first and the second emission module, the cooling system consisting of metal materials or high-optical-quality transparent materials.

10 . The laser system as claimed in claim 8 , comprising:
a first plurality of emission modules, parallel to one another and placed facing one another and coupled to a first receiving face (SR 1 ) of the laser medium, a second plurality of emission modules, parallel to one another and placed facing one another and coupled to a second receiving face (SR 2 ) of the laser medium,
the modules of the first plurality and of the second plurality furthermore being substantially parallel to one another, the propagation direction of the laser beam (Dp) being perpendicular to the emission modules,
the modules of the first plurality and of the second plurality being arranged in a quincunx.

11 . The laser system as claimed in claim 4 , wherein the laser cavity is designed such that the laser beam propagates in a plurality of different regions of the laser medium, a plurality of identical emission modules being arranged above each region.

12 . The laser system as claimed in claim 4 , comprising:
a first and a second prism coupled respectively to a laser face, said prisms being designed to deflect said laser beam such that it is guided by total internal reflection in said laser medium onto two faces, called edges (Tr), of dimensions e L ×L L ; a first set of emission modules coupled to the receiving face (SR) of the laser medium; a second set of emission modules (MEL) arranged on the laser medium in the horizontal plane (xy) and coupled to said edges (Tr), so as to perform coplanar pumping of the laser medium, a horizontal dimension of the laser beam being such that w b ≤w L sin θ h , where θ h is an angle of incidence of the beam incident on said laser edges.

13 . The system as claimed in claim 12 , wherein the emission modules of the second set are placed on said edges in a manner corresponding to regions of reflection of the laser beam guided in said laser medium.

14 . A laser amplifier comprising the laser pumping assembly as claimed in claim 1 , at least one emission module of the laser pumping assembly performing transverse pumping of the laser medium, a laser beam (FL) being incident on said laser amplifier and propagating in said laser medium in a propagation direction (Dp), passing through two opposing faces, called laser faces (SL), each having dimensions e L ×w L .

15 . The laser system as claimed in claim 12 , wherein the first set of emission mod

Assignees

• Centre Nat Rech Scient
• Inst Optique Theorique Appliquee
• Univ Paris Saclay

Inventors

• Balembois François
• Pichon Pierre

Classifications

• H01S3/1623

  chromium, e.g. Alexandrite · CPC title

• H01S3/08095

  Zig-zag travelling beam through the active medium · CPC title

• H01S3/0604 Primary

  in the form of a plate or disc · CPC title

• H01S3/0915

  by incoherent light · CPC title

• H01S3/1648

  with the formula XYZF6 (Colquiriite structure), wherein X is Li, Na, K or Rb, Y is Mg, Ca, Sr, Cd or Ba and Z is Al, Sc or Ga · CPC title