Despeckling of Continuous-Wave Lasers
An apparatus and method that reduces speckle from continuous-wave lasers by using stimulated Raman scattering in an optical fiber. The fiber core diameter and length are selected to achieve a desired output color and level of despeckling. Single-mode fiber may be utilized to achieve a sufficiently high power density to generate stimulated Raman scattering.
1 . An optical apparatus comprising:
an optical fiber; and
a continuous-wave laser light source;
wherein the continuous-wave laser light source illuminates the optical fiber; and a stimulated Raman scattering in the optical fiber enhances an aspect of a light output from the optical fiber.
2 . The apparatus of claim 1 wherein the aspect of the light output from the optical fiber is a speckle characteristic of the light output from the optical fiber.
3 . The apparatus of claim 2 wherein the optical fiber has a core diameter and a length and the core diameter and the length are selected to achieve the speckle characteristic.
4 . The apparatus of claim 1 wherein the aspect of the light output from the optical fiber is a color of the light output from the optical fiber.
5 . The apparatus of claim 4 wherein the optical fiber has a core diameter and a length and the core diameter and the length are selected to achieve the color.
6 . The apparatus of claim 1 wherein the optical fiber is a single-mode fiber.
7 . The apparatus of claim 1 further comprising:
a digital projector;
wherein the light output of the optical fiber illuminates the digital projector.
8 . The apparatus of claim 1 wherein an output wavelength of the continuous-wave laser light source is between 510 nm and 545 nm.
9 . The apparatus of claim 1 wherein the continuous-wave laser light source comprises a fiber laser.
10 . A method of despeckling comprising:
generating a laser beam from a continuous-wave laser;
focusing the laser beam into an optical fiber;
generating stimulated Raman scattering light in the optical fiber; and
using the stimulated Raman scattering light to enhance an aspect of a light output from the optical fiber.
11 . The method of claim 10 wherein the aspect of the light output from the optical fiber is a speckle characteristic of the light output from the optical fiber.
12 . The method of claim 11 wherein the optical fiber has a core diameter and a length and the core diameter and the length are selected to achieve the desired speckle characteristic.
13 . The method of claim 10 wherein the aspect of the light output from the optical fiber is a color of the light output from the optical fiber.
14 . The method of claim 13 wherein the optical fiber has a core diameter and a length and the core diameter and the length are selected to achieve the desired color.
15 . The method of claim 10 wherein the optical fiber is a single-mode fiber.
16 . The method of claim 10 further comprising:
using the stimulated Raman scattering light to illuminate a digital projector.
17 . The method of claim 10 wherein an output wavelength of the continuous-wave laser is between 510 nm and 545 nm.
18 . The method of claim 10 wherein the continuous-wave laser comprises a fiber laser.