Bragg grating elements for the conditioning of laser emission characteristics
Apparatus and methods for altering one or more spectral, spatial, or temporal characteristics of a light-emitting device are disclosed. Generally, such apparatus may include a volume Bragg grating (VBG) element that receives input light generated by a light-emitting device, conditions one or more characteristics of the input light, and causes the light-emitting device to generate light having the one or more characteristics of the conditioned light.
1. An optical element for receiving divergent light from a light emitting device, the light emitting device having a fast axis and a slow axis, the optical element comprising:
a three-dimensional bulk of material having a Bragg grating recorded therein, the Bragg grating having a periodic arrangement of flat grating planes;
wherein the bulk of material has a flat surface and the optical element has a cylindrical curved surface opposite the flat surface,
wherein the grating planes are located between the flat surface and the curved surface and are arranged to reflect a first portion of divergent light from the light emitting device that is incident on the flat surface of the bulk and such that a second portion of the incident light emerges from the optical element through the cylindrical curved surface such that divergence of the incident light is reduced along the fast axis of the light-emitting device.
2. The optical element of claim 1 , wherein the bulk of material is a photorefractive material.
3. The optical element of claim 2 , wherein the bulk of material is a sensitized silicate glass.
4. The optical element of claim 2 , wherein the Bragg grating is a holographic Bragg grating.
5. The optical element of claim 1 , further comprising a lens that is disposed on a second surface of the bulk of material opposite said flat surface.
6. The optical element of claim 1 , wherein the bulk of material has a curved surface opposite said flat surface, wherein the curved surface forms a cylindrical lens.
7. The optical element of claim 1 , wherein the incident light is collimated along the fast axis of the light emitting device.
8. The optical element of claim 7 , wherein the incident light is not collimated along the slow axis of the light-emitting device.
9. The optical element of claim 1 , wherein the incident light is not collimated along the slow axis of the light-emitting device.
10. The optical element of claim 5 , wherein the lens is attached to the second surface of the bulk of material.
11. The optical element of claim 1 , wherein the lens is formed from a second material that is distinct from the bulk of material in which the Bragg grating is recorded.