Hybrid laser

Details Hybrid laser Hybrid laser

1990-03-09

1991-09-10

Scott, Jr., Leon

Coherent light generators

Particular beam control device

Mode locking

372 6, 372 66, 372103, H01S 308

Patent

active

050480278

DESCRIPTION:

BRIEF SUMMARY
FIELD OF THE INVENTION

This invention relates to a system for effectively combining the output beams of a group of rod or slab lasers into a single laser beam of comparable quality and whose power is the sum of the output powers of the individual rod and slab lasers. The invention has application in the industrial and defence fields where powerful, scaleable laser beams are deployed.


SUMMARY OF THE PRIOR ART

Prior art rod lasers have suffered from scaling problems which severely limit and eventually prohibit their operation at high power levels. Firstly, the fact that the surface of a rod laser system can be more effectively cooled than its central region leads to the well known "thermal lensing" effect which in turn leads to severe beam distortion. Secondly, as the peak power of the laser pulse propogating through a rod laser medium increases, it eventually reaches the "self-focusing" threshold within the laser medium which results in the self collapse of said pulse into a fine filament, destroying the said rod laser medium in the process. The only way to avoid laser rod damage due to self-focusing is to limit the length of said rod to less than its "self-focusing" length at a given power level. Thirdly, many excellent laser media cannot be produced in bulk and one is, therefore, limited to small rods of such laser media in any case. Where the laser medium can be produced in large quantities, such as is the case with neodymiun doped glass, self-oscillation problems arise where the parasitic lasing actions deplete the stored energy within the excited laser medium before the arrival of the laser pulse to be amplified within said excited medium. In general the same problems apply to slabs of laser media as apply to rods, although, several specific laser slab configurations can avoid laser rod induced defects.
It follows that both prior art rod and slab lasers were very limited as far as the generation of laser beam powers were concerned. The fundamental defect of both prior art rod and slab lasers could be overcome to some extent in applications where the number of laser beams used was not a limitation. For example, in laser fusion studies it is possible to use a large number of laser beams to irradiate laser fusion pellets. This situation has led to the development of large, multi-beam laser systems worldwide in an effort to overcome the power restrictions of single beam laser systems. However, simply duplicating the individual arms of rod and slab lasers to produce more laser power is not a cost effective approach to scaling laser systems to high power levels. For example, a single arm of a large laser fusion system may cost $10 m. If one needs 100 such arms the cost suddenly shoots up to $1B and this prior art approach to scaling rod and slab lasers becomes prohibitively expensive. At the other end of the scale, excellent quality neodymiun doped yttrium aluminium garnet crystals can be grown and selected, but only crystals of very small volume. Obviously it is beneficial to combine the outputs of a series of such high quality crystalline lasers into a single beam format. However, prior art beam combining techniques cannot produce a single beam of similar quality whose total power is the sum of the power out of the individual crystal lasers.
The present invention overcomes the defects of prior art beam combining systems in that it automatically provides a single, scaleable, laser beam of similar, if not superior quality to that of the individual laser beams which it replaces. The invention achieves its superiority over prior art systems by coupling individual rod or slab laser media into a common scaleable output aperture using bundles of passive single mode optical fibres. The invention represents a parallel array of laser oscillators which have one common output aperture, the laser medium being represented by laser rods or slabs with the remainder of the resonant cavity between the laser mirrors being filled with coherently packed, passive bundles of single mode optical fibre whose cladding thickness

REFERENCES:
patent: 4383318 (1983-05-01), Barry et al.
patent: 4627068 (1986-12-01), Johnson et al.
patent: 4637025 (1987-01-01), Snitzer et al.
patent: 4682335 (1987-07-01), Hughes
patent: 4713822 (1987-12-01), Lee

Affiliated with

Also associated with

Rating

Hybrid laser does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Hybrid laser, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Hybrid laser will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-546324