"Optoelectronics diode-pumped rare gas lasers"
Abstract
In recent years, there have been conceited efforts to develop high-power diode-pumped alkali vapor lasers (DPAL) for weapons applications. These hybrid gas phase/ solid-state laser systems offer possibilities for constructing high-powered lasers with excellent beam quality. However, efforts to scale DPAL s have encountered two technical challenges that stem from the chemically aggressive nature of alkali metal vapors. The first problem is photo-induced chemical damage of the windows that confine the gain medium. The second is reaction of the alkali metal with the spin-orbit relaxation agent that sustains the population inversion (typically methane or ethane). This produces particulate matter in the gain medium ("laser snow"), and consumes both the hydrocarbon and the metal. Rare-gas atoms promoted to metastable electronically excited states have spectroscopic properties that are closely similar to those of the alkali metals. They are readily generated using low-power electrical discharges. The rare gases offer the advantages that they are unreactive, can be used at ambient temperatures, and can provide a range of laser wavelengths that have excellent atmospheric transmission characteristics. Spin-orbit relaxation can be accomplished using rare gas/ rare gas collisions. Consequently, it will be possible to construct closed-cycle lasers that have long-term stability (comparable to that of He/Ne, Ar+ and Kr+ lasers). Lasing of optically pumped Ar*, Kr* and Xe* has been demonstrated recently by the lead PI for this proposal. The proposed program is focused on the development of optically pumped rare gas lasers. This research will be carried out as a collaborative effort between Emory University (Prof. M. Heaven, lead PI), Tufts University (Dr. J. Hopwood), and Physical Sciences Inc. (Drs. T. Rawlins and S. Davis). Although they are not funded by this application, supporting research will be performed at the Air Force Research Laboratory/DELC (Dr. G. Pitz), the Air Force Institute of Technology (Prof. G. Perram) and the US Army Space and Missile Defense Command (Ms. Amanda Black). The primary objectives of the program are: I. Determinations of the optimal gas mixtures, pressures and discharge conditions for efficient lasing using pulsed excitation. 2. High-pressure discharge development. 3. Measurements of metastable transport, energy transfer and quenching rate constants. 4. CW rare gas laser systems demonstrations at multiple wavelengths. This sequence of tasks is designed to build the knowledge base that will guide the path to demonstrations of high-powered, diode pumped systems. The information obtained will be of fundamental value, suitable for publication in first-tier scientific journals. These projects will also provide excellent training opportunities for graduate students and post-doctoral fellows.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Sep 11, 2018
- Source ID
- W911NF1710427
Entities
People
- Michael C Heaven
Organizations
- Army Contracting Command
- Emory University
- United States Air Force