Mr. Rajiv Pandey Profile

Rajiv Pandey

Senior Product Manager

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Publications (5)

Proceedings Article | 25 February 2014 Paper

Narrow line diode laser stacks for DPAL pumping

Tobias Koenning, David Irwin, Dean Stapleton, Rajiv Pandey, Tina Guiney, Steve Patterson

Proceedings Volume 8962, 89620F (2014) https://doi.org/10.1117/12.2044723

KEYWORDS: Semiconductor lasers, Absorption, Diodes, High power diode lasers, Temperature metrology, Rubidium, Lithium, Electroluminescence, Alkali metals, Manufacturing

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Diode pumped alkali metal vapor lasers (DPALs) offer the promise of scalability to very high average power levels while maintaining excellent beam quality, making them an attractive candidate for future defense applications. A variety of gain media are used and each requires a different pump wavelength: near 852nm for cesium, 780nm for rubidium, 766nm for potassium, and 670nm for lithium atoms. The biggest challenge in pumping these materials efficiently is the narrow gain media absorption band of approximately 0.01nm. Typical high power diode lasers achieve spectral widths around 3nm (FWHM) in the near infrared spectrum. With state of the art locking techniques, either internal to the cavity or externally mounted gratings, the spectral width can typically be reduced to 0.5nm to 1nm for kW-class, high power stacks. More narrow spectral width has been achieved at lower power levels. The diode’s inherent wavelength drift over operating temperature and output power is largely, but not completely, eliminated. However, standard locking techniques cannot achieve the required accuracy on the location of the spectral output or the spectral width for efficient DPAL pumping. Actively cooled diode laser stacks with continuous wave output power of up to 100W per 10mm bar at 780nm optimized for rubidium pumping will be presented. Custom designed external volume holographic gratings (VHGs) in conjunction with optimized chip material are used to narrow and stabilize the optical spectrum. Temperature tuning on a per-bar-level is used to overlap up to fifteen individual bar spectra into one narrow peak. At the same time, this tuning capability can be used to adjust the pump wavelength to match the absorption band of the active medium. A spectral width of <0.1nm for the entire stack is achieved at <1kW optical output power. Tuning of the peak wavelength is demonstrated for up to 0.15nm. The technology can easily be adapted to other diode laser wavelengths to pump different materials.

Proceedings Article | 23 May 2013 Paper

Narrow-line, tunable, high-power diode laser pump for DPAL applications

Rajiv Pandey, David Merchen, Dean Stapleton, David Irwin, Chuck Humble, Steve Patterson, Heiko Kissel, Jens Biesenbach

Proceedings Volume 8733, 873307 (2013) https://doi.org/10.1117/12.2014301

KEYWORDS: Semiconductor lasers, Diodes, Diffraction, Diffraction gratings, Fiber Bragg gratings, High power lasers, Collimation, Temperature metrology, Rubidium

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Proceedings Article | 7 May 2012 Paper

Advancements in high-power diode laser stacks for defense applications

Rajiv Pandey, David Merchen, Dean Stapleton, Steve Patterson, Heiko Kissel, Wilhlem Fassbender, Jens Biesenbach

Proceedings Volume 8381, 83810G (2012) https://doi.org/10.1117/12.916743

KEYWORDS: Semiconductor lasers, Collimation, Diodes, Defense and security, Continuous wave operation, High power lasers, Laser applications, Electro optics, Indium

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Proceedings Article | 21 February 2011 Paper

Fiber coupled diode laser beam parameter product calculation and rules for optimized design

Zuolan Wang, Simon Drovs, Armin Segref, Tobias Koenning, Rajiv Pandey

Proceedings Volume 7918, 791809 (2011) https://doi.org/10.1117/12.875386

KEYWORDS: Diodes, Fiber lasers, Fiber couplers, Semiconductor lasers, Fiber coupled lasers, Optical design, Beam shaping, Optical simulations, Nomenclature, Technologies and applications

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Proceedings Article | 17 November 2005 Paper

Automated optical manufacturing test system for high power multi-bar diode modules

Sriraj Bhadra, Chuck Humble, Hoa Nguyen, Georg Treusch, Rajiv Pandey, John Bell

Proceedings Volume 5999, 59990O (2005) https://doi.org/10.1117/12.630729

KEYWORDS: Integrating spheres, Optics manufacturing, Semiconductor lasers, Sensors, Amplifiers, High power lasers, Lithium, Optical spheres, Data acquisition, Optical testing

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