Patent ID: 7633985

Claim:
Apparatus for altering a characteristic of a light-emitting device, the apparatus comprising: a light-emitting device having an emission spectrum; a cylindrical microlens that receives light emitted by the light-emitting device; and a three-dimensional optical element comprising a bulk of optical material and having a Bragg grating recorded in the bulk of optical material, wherein the three-dimensional optical element receives light directed from the microlens, the light received by the optical element having a first bandwidth, and redirects only a narrowband portion of the light received from the microlens, the redirected narrowband portion having a second bandwidth that is narrower than the first bandwidth, such that the redirected narrowband portion is fed back optically into the light-emitting device as a narrow-wavelength seed that causes a narrowing of the emission spectrum of the light-emitting device, and wherein the light emitting device has a fast axis and a slow axis, and wherein the microlens collimates the light emitted by the light-emitting device along the fast axis of the light-emitting device.