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Multimode-diode-pumped gas (alkali-vapor) laser

Description: We report the first demonstration of a multimode-diode-pumped gas laser--Rb vapor operating on the 795 nm resonance transition. Peak output of {approx}1 Watt was obtained using a volume-Bragg-grating stabilized pump diode array. The laser's output radiance exceeded the pump radiance by a factor greater than 2000. Power scaling (by pumping with larger diode arrays) is therefore possible.
Date: August 22, 2005
Creator: Page, R H; Beach, R J & Kanz, V K
Partner: UNT Libraries Government Documents Department

Hydrocarbon-free resonance transition 795-nm rubidium laser

Description: An optical resonance transition rubidium laser (5{sup 2}P{sub 1/2} {yields} 5{sup 2}S{sub 1/2}) is demonstrated with a hydrocarbon-free buffer gas. Prior demonstrations of alkali resonance transition lasers have used ethane as either the buffer gas or a buffer gas component to promote rapid fine-structure mixing. However, our experience suggests that the alkali vapor reacts with the ethane producing carbon as one of the reaction products. This degrades long term laser reliability. Our recent experimental results with a 'clean' helium-only buffer gas system pumped by a Ti:sapphire laser demonstrate all the advantages of the original alkali laser system, but without the reliability issues associated with the use of ethane.
Date: January 9, 2008
Creator: Wu, S Q; Soules, T F; Page, R H; Mitchell, S C; Kanz, V K & Beach, R J
Partner: UNT Libraries Government Documents Department

Resonance transition 795-nm Rubidium laser using 3He buffer gas

Description: We report the first demonstration of a 795-nm Rubidium resonance transition laser using a buffer gas consisting of pure {sup 3}He. This follows our recent demonstration of a hydrocarbon-free 795-nm Rubidium resonance laser which used naturally-occurring He as the buffer gas. Using He gas that is isotopically enriched with {sup 3}He yields enhanced mixing of the Rb fine-structure levels. This enables efficient lasing at reduced He buffer gas pressure, improving thermal management in high average power Rb lasers and enhancing the power scaling potential of such systems.
Date: August 2, 2007
Creator: Wu, S S; Soules, T F; Page, R H; Mitchell, S C; Kanz, V K & Beach, R J
Partner: UNT Libraries Government Documents Department

Developments toward a reliable diode-pumped hydrocarbon-free 795-nm rubidium laser

Description: We report a 795-nm diode-pumpable Rb laser using a buffer gas of pure {sup 3}He. {sup 3}He gas enhances mixing of the Rb fine-structure levels. This enables efficient lasing at reduced He pressures and improved thermal management.
Date: May 7, 2008
Creator: Wu, S S; Soules, T F; Page, R H; Mitchell, S C; Kanz, V K & Beach, R J
Partner: UNT Libraries Government Documents Department

Optical tuning a dichroic multilayer for a high fluence laser application

Description: We report on the design and successful fabrication of a dichroic multilayer stack using a procedure that allowed shifting from high reflectance to high transmittance within 89 rim and surviving high laser fluences. A design approach based on quarter-wave thick layers allowed the multilayer stack to be optically tuned in the last layers of the stack. In our case, this necessitated removing the samples from the coating chamber for a transmittance scan prior to depositing the last layers. This procedure is not commonly practiced due to thermal stress-induced failures in an oxide multilayer. However, D.J. Smith and co-workers reported that reactive e-beam evaporated hafnia from a Hf source produced laser-resistant coatings that had less coating stress compared to coatings evaporated from a HfO{sub 2} source. Tuned dichroic coatings were made that had high transmittance at 941 rim and high reflectance at 1030 nm. The coating was exposed for 5 minutes to a 100 kW/cm{sup 2} 1064 nm (180-ns pulsewidth, 10.7 kHz) laser beam and survived without microscopic damage. The same coating survived a 140 kW/cm{sup 2} of laser intensity without catastrophic damage before optical tuning were performed.
Date: October 11, 1995
Creator: R. Chow, Loomis, G.E.; Bibeau, C.; Molau, N.E.; Kanz, V.K. & Beach, R.J.
Partner: UNT Libraries Government Documents Department

Performance results on the laser portion of the Keck laser guide star system

Description: The Laser Guide Star (LGS) system for the Keck II, 10 m telescope consists of two separate but interconnected systems, the laser and the adaptive optics bench. The laser portion of the LGSl is a set of five frequency doubled YAG lasers pumping a master oscillator-power amplifier dye chain to produce up to 30 W of 589 p at 26 kHz of tuned light. Presently the laser system has been set up at the Keck facility in Waimea, HI and is undergoing test and evaluation. When it will be set up on the Keck II telescope, the pump lasers, dye master oscillator and associated control equipment will be located on the dome floor and the dye laser amplifiers, beam control system and diagnostics will be mounted directly on the telescope as shown in Fig. 1, Extensive use of fiber optics for both transmission of the oscillator pulse and the pump laser light has been used.
Date: September 29, 1998
Creator: Cooke, J B; Danforth, P M; Erbert, G V; Feldman, M; Friedman, H W; Gavel, D T et al.
Partner: UNT Libraries Government Documents Department

Improved performance of the laser guide star adaptive optics system at Lick Observatory

Description: Results of experiments with the laser guide star adaptive optics system on the 3-meter Shane telescope at Lick Observatory have demonstrated a factor of 4 performance improvement over previous results. Stellar images recorded at a wavelength of 2 {micro}m were corrected to over 40% of the theoretical diffraction-limited peak intensity. For the previous two years, this sodium-layer laser guide star system has corrected stellar images at this wavelength to {approx}10% of the theoretical peak intensity limit. After a campaign to improve the beam quality of the laser system, and to improve calibration accuracy and stability of the adaptive optics system using new techniques for phase retrieval and phase-shifting diffraction interferometry, the system performance has been substantially increased. The next step will be to use the Lick system for astronomical science observations, and to demonstrate this level of performance with the new system being installed on the 10-meter Keck II telescope.
Date: July 20, 1999
Creator: An, J R; Avicola, K; Bauman, B J; Brase, J M; Campbell, E W; Carrano, C et al.
Partner: UNT Libraries Government Documents Department