Jun. 27, 2002 HAPSL Workshop: Sarnoff Presentation ( 1 J.H. Abeles and V.B. Khalfin Photonic ICs and Components Organization Sarnoff Corporation 201 Washington Rd., Princeton, NJ 08543 USA [email protected], (609) 734-2571 High Average Power Solid-state Laser (HAPSL) DARPA/MTO Diode Pump Workshop Dr. M. Stickley, Program Manager Booz, Allen & Hamilton, 3811 Fairfax Dr., Arlington, VA 22203 June 27, 2001 Considerations for Realization of High Power Conversion Efficiency in Diode Lasers
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Jun. 27, 2002HAPSL Workshop: Sarnoff Presentation (6-27-02)1 J.H. Abeles and V.B. Khalfin Photonic ICs and Components Organization Sarnoff Corporation.
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• Example of the Sarnoff Track Record Example of the Sarnoff Track Record Innovating New Paradigms for Laser Performance OptimizationInnovating New Paradigms for Laser Performance Optimization
Potential Defect: A Challenge… and the opportunity ...
• A 0.25 volt potential defect represents only 10 kT at 300° K
• But it brings maximum wallplug efficiency from 100% to 85%
• Barrier cannot be eliminatedConfinement of minority carriersWaveguiding
• Barrier is enhanced in high power broadened waveguide (owing to ambipolar diffusion effect)
• Interesting: A shorter wavelength laser (e.g., 400 nm) may permit greater efficiency -- owing to the fact that the potential defect is expressed in kT which is 0.025 eV regardless of .`
• Achieving 85% power conversion efficiency at 940 nm can only be achieved by fundamental new advances in laser design lower losses alone won’t do the job lower contact resistance alone won’t do the job as long as voltage defect is 10 kT,
maximum theoretical efficiency is only ~82% N.B.: at 380 nm could achieve 90%
• Any successful approach must optimize transport of carriers into the quantum well while preserving other necessary features Systematic Design for Minimization of barriers? Material which provides no barrier to majority carriers but
high barrier for minority carriers (c.b./v.b. offset engineering) Bandgap engineering (miniband as in q. cascade)? The third dimension (lateral current injection)? Matter waves?