Whiting N.,Southern Illinois University Carbondale |
Whiting N.,University of Nottingham |
Nikolaou P.,Southern Illinois University Carbondale |
Nikolaou P.,Vanderbilt University |
And 8 more authors.
Applied Physics B: Lasers and Optics | Year: 2012
Next-generation laser diode arrays with integrated 'on-chip' volume holographic gratings can provide high power with spectrally narrowed output that can be tuned about the rubidium D 1 line - without causing significant changes to the laser's flux or spectral profile. These properties were exploited to independently evaluate the effects of varying the laser centroid wavelength and power on batch-mode Rb/ 129Xe spin-exchange optical pumping (SEOP) as functions of xenon partial pressure and cell temperature. Locally optimized SEOP was often achieved with the laser tuned to either the red or blue side of the Rb D 1 line; global optimization of SEOP was observed at lower cell temperatures and followed the D 1 absorption profile, which was asymmetrically broadened and red-shifted from the nominal wavelength. The complex dependence of the optimal wavelength for laser excitation on the cell temperature and Xe density appears to result from an interplay between cell illumination and the Rb/ 129Xe spin-exchange rate, as well as [Xe] cell-dependent changes to the Rb absorption lineshape that are in qualitative agreement with expectations based on previous work [Romalis et al., Phys. Rev. A, 56:4569-4578, (1997)], but significantly greater in magnitude. These next-generation lasers provide a ∼2-3-fold improvement in 129Xe polarization compared to conventional broadband lasers. © Springer-Verlag 2012.
Gallup K.,Laser Operations, LLC |
Ungar J.,Laser Operations, LLC |
Vaissie L.,Laser Operations, LLC |
Lammert R.,Laser Operations, LLC |
Hu W.,Laser Operations, LLC
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2012
Diode lasers in the 1400 nm to 1600 nm regime are used in a variety of applications including pumping Er:YAG lasers, range finding, materials processing, aesthetic medical treatments and surgery. In addition to the compact size, efficiency, and low cost advantages of traditional diode lasers, high power semiconductor lasers in the eye-safe regime are becoming widely used in an effort to minimize the unintended impact of potentially hazardous scattered optical radiation from the laser source, the optical delivery system, or the target itself. In this article we describe the performance of high efficiency high brightness InP laser bars at 1470nm and 1550nm developed at QPC Lasers for applications ranging from surgery to rangefinding. © 2012 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).
Agency: Department of Defense | Branch: Army | Program: SBIR | Phase: Phase II | Award Amount: 728.09K | Year: 2011
Efficient electrically pumped eye-safe lasers for battlefield applications require high brightness, spectrally stabilized fiber-coupled pump lasers emitting near 1500 nm. Existing 1500 nm pump lasers are spectrally unstabilized, have poor efficiency and brightness and require cooling. Using new diode quantum-well designs and high thermal and optical coupling approaches, we will demonstrate a new generation of pump modules which provide unprecedented power and brightness but operate at high ambient temperatures without cooling.
Agency: Department of Defense | Branch: Navy | Program: SBIR | Phase: Phase I | Award Amount: 79.11K | Year: 2013
As part of an effort funded by HEL-JTO, we recently demonstrated advanced quantum well diode laser designs with enhanced confinement operating at 1500 nm that substantially advanced the state-of-the-art with regard to efficiency, high operating temperature and beam quality. Similar enhanced confinement designs will be implemented at 808 nm to greatly improve both electrical-to-optical efficiency and fiber-coupling efficiency. Moreover, by incorporating monolithic internal diffraction gratings in these lasers, linewidths and wavelength tolerances can be reduced by roughly a factor of 4 compared to standard pump diodes without incurring the cost and complication of external volume bragg grating stabilizers.
Agency: Department of Defense | Branch: Missile Defense Agency | Program: SBIR | Phase: Phase II | Award Amount: 998.12K | Year: 2014
Diode Pumped Alkali Vapor Lasers (DPAL) are a promising technology for high power directed energy lasers because of several favorable characteristics, notably the small quantum defect which results in very little deposition of waste heat in the lasing medium and potentially good conversion efficiency and beam quality. Existing diode pumps have spectra that are too wide and inaccurately controlled, so external stabilization schemes using external volume gratings is required, but the spectral narrowing and tuning range provided is too limited and cost is too high. Building on a successful Phase I demonstration, we will develop high power internally stabilized pump diode bars for alkali pumping with sub-GHz linewidths and tuning rates of 80 pm/degree and which provide scalability to multi-kW stacks.
Agency: Department of Defense | Branch: Defense Advanced Research Projects Agency | Program: SBIR | Phase: Phase I | Award Amount: 149.13K | Year: 2012
High brightness directed energy lasers based on combining beams generated by fiber lasers and amplifiers require fiber-coupled 976 nm diode laser pumps with spatial and spectral brightness that exceed current state-of-the-art. We will meet these requirements by adapting 1060 nm MOPA designs with which we have demonstrated operation at brightness approaching 1 GW/cm^2*sr, to 976 nm.
Agency: Department of Defense | Branch: Defense Advanced Research Projects Agency | Program: SBIR | Phase: Phase II | Award Amount: 1.74M | Year: 2014
Using a unique high power diffraction-limited spectrally tailored diode platform, we are developing 976 nm fiber-coupled pump modules with extremely high spatial and spectral brightness characteristics.
Agency: Department of Defense | Branch: Missile Defense Agency | Program: SBIR | Phase: Phase I | Award Amount: 99.63K | Year: 2011
Diode-pumped Alkali Lasers (DPAL) have recently gained attention as highly-efficient lasers due to the very small energy differences between the pump and lasing levels (2% for Rb and 5% for Cs). Pump arrays with narrow spectral outputs with linewidths below 0.2 nm and which can be accurately tuned to Rb or Cs absorption lines are required, but conventional arrays have spectral widths as wide as 10 nm. Linewidth narrowing methods using Volume Bragg Gratings provide limited tunability, limited spectral locking, poor manufacturability and high cost but, maybe most importantly, do not provide a realistic path towards power levels and volumes required for tactical operations of HEL. We propose to develop very narrow linewidth, temperature tunable 780 nm pump arrays using novel on-chip wavelength stabilized high brightness diode arrays. This design provides very narrow linewidth, high power output and ease of temperature tunability in a monolithic, easily manufactured low cost diode array that is scalable to hundreds of kW level.
Agency: Department of Defense | Branch: Navy | Program: SBIR | Phase: Phase I | Award Amount: 79.68K | Year: 2012
Recent advances in diode laser quantum-well designs have demonstrated significantly increased operating temperatures with good efficiency at wavelengths ranging from 808 to 1500 nm. Similar quantum-well designs will be adapted to 976 nm with the goal of achieving 70% wallplug efficiency at 80 C.
Laser Operations, LLC | Date: 2010-11-09
Lasers not for medical use; semiconductor lasers not for medical use; diode lasers not for medical use. Lasers for medical use; semiconductor lasers for medical use; diode lasers for medical use.