METHOD AND SYSTEM FOR COMBINING MULTIPLE LASER BEAMS USING TRANSMISSION HOLOGRAPHIC METHODOLOGIES

• US 20060109876A1
• Filed: 11/22/2004
• Published: 05/25/2006
• Est. Priority Date: 11/22/2004
• Status: Abandoned Application

• Current Assignee: Selim Shahriar
• Original Assignee: Selim Shahriar
• Inventors: Andrews, Mark, Donoghue, John
• Application Number:
  US10/904,669
• Publication Number:
  US 20060109876A1
• Time in Patent Office: Days
• US Class Current: 372/32
• CPC Class Codes: G02B 19/0009 having refractive surfaces only
• CPC Class Codes: G02B 19/0028 refractive and reflective surfaces, e.g. non-imaging catadioptric systems
• CPC Class Codes: G02B 19/0057 in the form of a laser diode array, e.g. laser diode bar semiconductor laser arrays with beam combining arrangement H01S5/4012
• CPC Class Codes: G02B 27/0944 Diffractive optical elements, e.g. gratings, holograms gratings per se G02B5/18; holograms used as optical elements per se G02B5/32
• CPC Class Codes: G02B 27/1086 operating by diffraction only
• CPC Class Codes: G02B 27/1093 for use with monochromatic radiation only, e.g. devices for splitting a single laser source
• CPC Class Codes: G02B 5/32 Holograms used as optical elements
• CPC Class Codes: G03H 1/0248 Volume holograms
• CPC Class Codes: G03H 1/28 superimposed holograms only
• CPC Class Codes: G03H 2001/0439 for recording Holographic Optical Element [HOE] HOE per se G02B5/32
• CPC Class Codes: H01S 5/4012 Beam combining, e.g. by the use of fibres, gratings, polarisers, prisms
• CPC Class Codes: H01S 5/4025 Array arrangements, e.g. constituted by discrete laser diodes or laser bar H01S5/42 takes precedence
• CPC Class Codes: H01S 5/4056 emitting light in more than one direction
• CPC Class Codes: H01S 5/4062 with an external cavity or using internal filters, e.g. Talbot filters

Abstract

The Holographic Beam Combiner, (HBC), is used to combine the output from many lasers into a single-aperture, diffraction-limited beam. The HBC is based on the storage of multiple holographic gratings in the same spatial location. By using a photopolymer material such as quinone-doped polymethyl methacrylate (PMMA) that uses a novel principle of “polymer with diffusion amplification” (PDA), it is possible to combine a large number (N) of diode lasers, with an output intensity and brightness 0.9 N times as much as those of the combined outputs of individual N lasers. The HBC will be a small, inexpensive to manufacture, and lightweight optical element. The basic idea of the HBC is to construct multiple holograms onto a recording material, with each hologram using a reference beam incident at a different angle, but keeping the object beam at a fixed position. When illuminated by a single read beam at an angle matching one of the reference beams, a diffracted beam is produced in the fixed direction of the object beam. When multiple read beams, matching the multiple reference beams are used simultaneously, all the beams can be made to diffract in the same direction, under certain conditions that depend on the degree of mutual coherence between the input beams.

Claims

1. A method &

system comprising;

means for generating a plurality of laser beams at multiple frequencies; and

providing a stable, all optic feedback control so as to lock the frequencies of the plurality of laser beams.

2. A method &

system comprising;

a plurality of stages of laser sources cascading two or more stages of laser sources so as to generate laser beams that are combined using in each stage a single holographic substrate containing multiple gratings in order to reach at least ten watts of power output.

3. A method &

system according to claim 2, wherein the combined beam to reach at least hundred watts of power output.

4. A method &

system according to claim 2, wherein the combined beam to reach at least thousand watts of power output.

5. A method &

system comprising;

a plurality of N laser sources and (N−

1) individual holographic gratings in a cascaded arrangement so as to yield a single combined laser beam with at least ten watts of power output.

6. A method &

system according to claim 5, wherein the combined beam to reach at least hundred watts of power output.

7. A method &

system according to claim 5, wherein the combined beam to reach at least thousand watts of power output.