Apparatus and methods for altering a characteristic of a light-emitting device
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. Apparatus for altering a characteristic of a light-emitting device, the apparatus comprising:
a light-emitting device having a gain medium;
a folding reflector;
a retro-reflector;
a Bragg grating element having a peak wavelength; and
rotation means for rotating the Bragg grating element and folding reflector,
wherein the Bragg grating element receives a first portion of light emitted by the light-emitting device and redirects a second portion of light that is less than the first portion at an angle onto the folding reflector, the folding reflector redirects the second portion of light along a path to the retro-reflector, and the retro-reflector reflects the second portion of redirected light back along the path into the gain medium of the light-emitting device, thus causing the light-emitting device to operate at the peak wavelength of the Bragg grating element, and
wherein rotation of the Bragg grating element and folding reflector continuously tunes the wavelength of light emitted by the light-emitting device.
2. Apparatus according to claim 1 , wherein the Bragg grating element is a reflective Bragg grating element.
3. Apparatus according to claim 1 , wherein the Bragg grating element is a transmissive Bragg grating element.
4. Apparatus according to claim 1 , wherein folding reflector is a folding mirror.
5. Apparatus according to claim 1 , wherein the Bragg grating element has a clear aperture and a period and peak wavelength that vary smoothly and continuously as a function of position across its clear aperture.
6. Apparatus according to claim 1 , further comprising a first lens that collimates the light emitted by the light-emitting device onto the Bragg grating element.
7. Apparatus for altering a characteristic of a light-emitting device, the apparatus comprising:
a light-emitting device having a gain medium;
a folding reflector;
a retro-reflector;
a Bragg grating element having a peak wavelength and a non-zero diffraction order; and
rotation means for rotating the Bragg grating element and folding reflector,
wherein the Bragg grating element receives light emitted by the light-emitting device and redirects the received light at an angle onto the folding reflector, the folding reflector redirects the light along a path to the retro-reflector, and the retro-reflector reflects the redirected light back along the path into the gain medium of the light-emitting device, thus causing the light-emitting device to operate at the peak wavelength of the Bragg grating element, and
wherein rotation of the Bragg grating element and folding reflector continuously tunes the wavelength of light emitted by the light-emitting device.
8. Apparatus according to claim 7 , wherein the Bragg grating element is a reflective Bragg grating element.
9. Apparatus according to claim 7 , wherein the Bragg grating element is a transmissive Bragg grating element.
10. Apparatus according to claim 7 , wherein folding reflector is a folding mirror.
11. Apparatus according to claim 7 , wherein the Bragg grating element has a clear aperture and a period and peak wavelength that vary smoothly and continuously as a function of position across its clear aperture.
12. Apparatus according to claim 7 , farther comprising a first lens that collimates the light emitted by the light-emitting device onto the Bragg grating element.
13. Apparatus for altering a characteristic of a light-emitting device, the apparatus comprising:
a light-emitting device having a gain medium;
a folding reflector;
a retro-reflector;
a volume Bragg grating having a peak wavelength and a Bragg plane within the volume Bragg grating; and
rotation means for rotating the volume Bragg grating and folding reflector, wherein the Bragg plane within the volume Bragg grating and the folding reflector define a pivot point of the rotation means,
wherein the Bragg plane within the volume Bragg grating receives light emitted by the light-emitting device and redirects the received light at an angle onto the folding reflector, the folding reflector redirects the light along a path to the retro-reflector, and the retro-reflector reflects the redirected light back along the path into the gain medium of the light-emitting device, thus causing the light-emitting device to operate at the peak wavelength of the Bragg grating element, and
wherein rotation of the Bragg grating element and folding reflector continuously tunes the wavelength of light emitted by the light-emitting device.
14. Apparatus according to claim 13 , wherein the volume Bragg grating is a reflective Bragg grating element.
15. Apparatus according to claim 13 , wherein the volume Bragg grating is a transmissive Bragg grating element.
16. Apparatus according to claim 13 , wherein the volume Bragg grating defines an outer surface through which the light emitted by the light-emitting device is received, and wherein the Bragg plane is parallel to the outer surface.
17. Apparatus according to claim 13 , wherein the volume Bragg grating defines an outer service through which the light emitted by the light-emitting device is received, and wherein the Bragg plane is perpendicular to the outer surface.
18. Apparatus according to claim 13 , wherein folding reflector is a folding mirror.
19. Apparatus according to claim 13 , wherein the Bragg plane has a clear aperture and a period and peak wavelength that vary smoothly and continuously as a function of position across its clear aperture.
20. Apparatus according to claim 13 , further comprising a first lens that collimates the light emitted by the light-emitting device onto the Bragg plane.