Coherent light generators – Particular resonant cavity – Specified cavity component
Reexamination Certificate
1999-09-15
2001-04-24
Scott, Jr., Leon (Department: 2881)
Coherent light generators
Particular resonant cavity
Specified cavity component
C372S009000, C372S098000, C372S107000, C372S108000
Reexamination Certificate
active
06222872
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to the use of lens ducts to deliver pump light to laser gain materials, and more specifically, it relates to means for delivering pump light to a laser gain element while maintaining access for a laser or probe beam.
2. Description of Related Art
The design of solid-state lasers is greatly determined by the architecture for pump light delivery and similarly, the brightness (W/cm2-steradian) of pump light. For instance, some devices utilize pump light impinging on a face of a slab or along the barrel of a rod in a geometry commonly referred to as side-pumping. However, in some cases, it is desirable to utilize an end-pumping geometry in order to achieve high delivery efficiency, or due to limitations in the absorption length due to dopant concentration.
Because of limitations in diode array brightness, it is often desirable to confine the pump light in the gain element via total internal reflection (TIR), since the Rayleigh range may be much less than the absorption length. The limited diode brightness also places limitations on access to the laser beam if the pump light fills the entire cross-sectional area of the gain element. One geometry for diode-array end-pumping uses a dichroic coating on one endface of the laser gain element to achieve high reflectivity at the laser wavelength and high transmission for the pump wavelength over its angular distribution. This allows the pump light to be delivered through this endface while the laser beam is reflected off of the same face and extracted from the laser medium through another face, usually the other endface. However, the use of the dichroic coating places restrictions on how close the pump and laser wavelengths can be, as well as the angular distribution of the pump light. In addition, there are situations where pump light enters the gain element through a surface and it would be desirable to access the laser beam through the same surface, for instance to pump both ends of a slab or rod.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an intermediate beam extractor (IBE).
It is another object of the present invention to provide means to access a laser beam through the pumped face of a laser gain element by appropriate design of the gain element and the pump delivery optical train.
Still another object of the invention is to provide designs for laser amplifiers and laser oscillators that utilize one or more lensing ducts and one or more intermediate beam extractors such that pump light may be delivered to a gain medium while maintaining access to the laser beam.
Another object of the invention is to provide an intermediate beam extractor with turning mirrors made therein to redirect light back into the laser gain medium.
It is another object of the invention to provide laser oscillators and amplifiers that utilize on each end of a laser gain medium a laser diode array optical pump source directed through a lensing duct and an intermediate beam extractor while maintaining access the the laser beam.
Another object of the invention is to provide a dot mirror placed on an intermediate beam extractor such that pump light is funneled around the dot mirror.
The invention is an intermediate beam extractor (IBE). A lens duct is used to deliver pump light through the IBE into a laser gain medium. The laser beam is accessed through the intermediate beam extractor which can be implemented as part of the gain element, part of the lens duct or a separate component entirely. The IBE comprises an optically transparent material and a plurality of continuously extending flat sides interconnecting the first and second end faces of the IBE. The first end face has a greater cross-section than the second end face and the first end face has a greater cross-section than the smaller cross-section area end face of a lensing duct. The first end of the IBE is positioned to receive a pump beam after it exits the smaller cross-section area end of the lensing duct. U.S. Pat. No. 5,307,430, titled “Lensing Duct”, describes the lensing duct in detail.
The intermediate beam extractor is included in several embodiments of lasers and laser amplifiers. One embodiment is an apparatus, comprising a lensing duct having an optically transparent material, first and second ends and a plurality of continuously extending flat sides interconnecting the ends, where said one end of the lensing duct has a greater cross-section than the other end. A laser diode array is used for production of a pump laser beam, where the laser diode array is configured to direct the pump laser beam onto the larger cross-section end of the lensing duct and the pump laser beam exits from the smaller cross-section end of the lensing duct. The IBE is positioned to receive the pump beam after it exits from the smaller cross-section end of the lensing duct. A laser gain medium is positioned to receive the pump laser beam after it exits the IBE.
A dual-end-pumped slab laser gain module has been designed where pump light is delivered to both ends of a slab gain element with the laser beam entering and exiting at an angle greater than that of the pump light. An important aspect of the design is the means to extract the laser beam with minor impact on pump delivery efficiency. The additional optical component can be fabricated as part of the gain element or as a separate component. The optical components may also have beneficial properties in suppressing parasitic modes, in addition to their purpose of pump light delivery and laser beam extraction.
REFERENCES:
patent: 5307430 (1994-04-01), Beach et al.
patent: 6049558 (2000-04-01), Harada et al.
Beach Raymond J.
Honea Eric C.
Payne Stephen A.
Jr. Leon Scott
Scott Eddie E.
The Regents of the University of California
Thompson Alan H.
LandOfFree
Delivering pump light to a laser gain element while... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Delivering pump light to a laser gain element while..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Delivering pump light to a laser gain element while... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2495030