Diode Pumped Alkali Vapor Lasers - A New Pathway to High Beam Quality at High Average Power
Resonance-transition alkali-vapor lasers have only recently been demonstrated [1] but are already attracting considerable attention. Alkali-atom-vapor gain media are among the simplest possible systems known, so there is much laboratory data upon which to base performance predictions. Therefore, accurate modeling is possible, as shown by the zero- free-parameter fits [2] to experimental data on alkali-vapor lasers pumped with Ti:sapphire lasers. The practical advantages of two of the alkali systems--Rb and Cs--are enormous, since they are amenable to diode-pumping [3,4]. Even without circulating the gas mixture, these lasers can have adequate cooling built-in owing to the presence of He in their vapor cells. The high predicted (up to 70%) optical-to-optical efficiency of the alkali laser, the superb (potentially 70% or better) wall-plug efficiency of the diode pumps, and the ability to exhaust heat at high temperature (100 C) combine to give a power-scalable architecture that is lightweight. A recent design exercise [5] at LLNL estimated that the system ''weight-to-power ratio'' figure of merit could be on the order of 7 kg/kW, an unprecedented value for a laser of the 100 kW class. Beam quality is expected to be excellent, owing to the small dn/dT value of the gain medium. There is obviously a long way to go, to get from a small laser pumped with a Ti:sapphire or injection-seeded diode system (of near-perfect beam quality, and narrow linewidth) [1, 4] to a large system pumped with broadband, multimode diode- laser arrays. We have a vision for this technology-development program, and have already built diode-array-pumped Rb lasers at the 1 Watt level. A setup for demonstrating Diode-array-Pumped Alkali vapor Lasers (DPALs) is shown in Figure 1. In general, use of a highly-multimode, broadband pump source renders diode-array-based experiments much more difficult than the previous ones done with Ti:sapphire pumping. High-NA optics, short focal distances, and short vapor cells are needed.
- Research Organization:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- US Department of Energy (US)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 15016696
- Report Number(s):
- UCRL-PROC-212117; TRN: US200515%%806
- Resource Relation:
- Conference: Presented at: Solid State and Diode Laser Technology Review, Los Angeles, CA (US), 06/07/2005--06/09/2005; Other Information: PBD: 6 May 2005
- Country of Publication:
- United States
- Language:
- English
Similar Records
Army Solid State Laser Program: Design, Operation, and Mission Analysis for a Heat-Capacity Laser
Development of Trivalent Ytterbium Doped Fluorapatites for Diode-Pumped Laser Applications