Method and device for adjusting wavelength distribution pattern in laser
A plurality of configurations is simultaneously formed in a material by a single laser beam having a desired distribution pattern of wavelengths. An input laser beam has an initial wavelength distribution pattern. The initial wavelength distribution pattern is adjusted or modified into a desired final wavelength distribution pattern. For example, the initial wavelength distribution pattern is a wide range of wavelengths in a single bell-curve distribution while the desired final wavelength distribution pattern has a specific number of sharp peaks each over a predetermined narrow range. The laser beam having the desired final wavelength distribution pattern is focused upon on a material. Because of the multiple peaks in the wavelength distribution, the laser beam is focused at a plurality of the focal distances. A number of structures is simultaneously formed in a material at the multiple focal points or at multiple locations/depths when the above laser beam is projected onto the material.
1. A method of processing a material by a laser beam, comprising the steps of:
inputting a laser beam having a first predetermined number of peaks over a predetermined range of wavelengths in a first distribution pattern;
modifying the first distribution pattern to a second redistribution pattern that has a predetermined desired distribution pattern having a second predetermined number of peaks over the predetermined range of the wavelengths;
focusing over the material the laser beam having the desired redistribution pattern of the wavelengths; and
simultaneously forming a predetermined set of configurations at a different depth from a surface of the material by the focused laser beam.
2. The method of processing a material by a laser beam according to claim 1 wherein said modifying step further comprises additional steps of:
spatially separating the laser beam into at least two laser beams, each of the laser beams having a sharp peak over a predetermined narrow range of the wavelengths; and
merging the two laser beams into a single laser beam having at least two of the sharp peaks each over a predetermined narrow range of the wavelengths.
3. The method of processing a material by a laser beam according to claim 2 wherein said focusing step focuses the merged single laser beam on at least two focal points.
4. The method of processing a material by a laser beam according to claim 3 wherein the focal points are each located at a different depth with respect to a surface of the material.
5. The method of processing a material by a laser beam according to claim 3 wherein the focal points are each located at a different position with respect to a surface of the material.
6. The method of processing a material by a laser beam according to claim 3 wherein the focal points are each located at a combination of different depths and positions with respect to a surface of the material.
7. The method of processing a material by a laser beam according to claim 1 wherein said simultaneously processing step further comprises an additional step of scanning the focused laser beam.
8. The method of processing a material by a laser beam according to claim 1 wherein said simultaneously processing step further comprises an additional step of moving the material with respect to the focused laser beam.
9. The method of processing a material by a laser beam according to claim 1 further comprising an additional step of controlling a passage of a certain portion of the laser beam having the desired redistribution pattern of the wavelengths prior to said focusing step.
10. The method of processing a material by a laser beam according to claim 8 wherein said input step, said modifying step and said moving step are synchronously coordinated.
11. The method of processing a material by a laser beam according to claim 1 wherein the first distribution pattern is a broad range of the wavelengths in a bell-shaped distribution pattern, the second distribution pattern being a predetermined number of narrow ranges of the wavelengths each in a sharp peak.