Mirror structure and laser device comprising such a mirror structure
First Claim
1. Laser mirror structure intended to define a laser cavity and comprising a multilayer and a resonant grating mirror formed by a grating associated with a waveguide propagating at least a guided mode, wherein said resonant grating mirror and said multilayer are arranged for acting together as a transverse mode selector of the laser cavity, the resonant grating mirror being highly reflective only for a narrow angular spectrum centered at a given incidence angle so that this resonant grating mirror defines an angularly selective mirror, said multilayer being arranged for adjusting the reflectivity of the laser mirror structure over a broad angular spectrum including said narrow angular spectrum, this reflectivity being selected so as to allow the lasing in said laser cavity of a determined transverse mode having substantially its angular spectrum contained in said narrow angular spectrum of said resonant grating mirror but to prevent the lasing of higher modes having their angular spectrum substantially wider than said narrow angular spectrum.
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Accused Products
Abstract
For increasing the power emitted by surface emitting lasers and for improving the spatial coherence of the laser beam, emitted in particular by disk lasers, microchip lasers and VCSELs having a relatively wide emitting area, the invention proposes to select a low order transverse cavity mode by means of a mirror structure (12) of high reflectivity, and of high angular selectivity. The mirror structure comprises a multilayer (14) receiving the optical beam (24) and a resonant grating mirror (16) following the multilayer and arranged for highly reflecting the optical beam in a narrow angular range at each side of a determined incidence angle.
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Citations
11 Claims
- 1. Laser mirror structure intended to define a laser cavity and comprising a multilayer and a resonant grating mirror formed by a grating associated with a waveguide propagating at least a guided mode, wherein said resonant grating mirror and said multilayer are arranged for acting together as a transverse mode selector of the laser cavity, the resonant grating mirror being highly reflective only for a narrow angular spectrum centered at a given incidence angle so that this resonant grating mirror defines an angularly selective mirror, said multilayer being arranged for adjusting the reflectivity of the laser mirror structure over a broad angular spectrum including said narrow angular spectrum, this reflectivity being selected so as to allow the lasing in said laser cavity of a determined transverse mode having substantially its angular spectrum contained in said narrow angular spectrum of said resonant grating mirror but to prevent the lasing of higher modes having their angular spectrum substantially wider than said narrow angular spectrum.
Specification