Dr. Mitchell H. Fields Profile

Dr. Mitchell H. Fields

Vice President and General Manager at Broadcom Inc

SPIE Involvement:

Author

Proceedings Article | 21 July 2000 Paper

Initial results from the Advanced-Concepts Laboratory for adaptive optics and tracking

Mitchell Fields, Jan Kansky, Robert Stock, Diane Powers, Paul Berger, Charles Higgs

Proceedings Volume 4034, (2000) https://doi.org/10.1117/12.391862

KEYWORDS: Adaptive optics, Atmospheric propagation, Missiles, Turbulence, Fiber optic illuminators, Wave propagation, CCD image sensors, Phase measurement, CCD cameras, Composites

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Proceedings Article | 10 May 1996 Paper

Enhancing stimulated Raman scattering of weaker gain Raman modes in microdroplets by seeding and efficient pumping

Md. Mohiuddin Mazumder, Mitchell Fields, Justin Hartings, Xiaoyun Pu, Alfred Kwok, Karl Schaschek, Richard Chang

Proceedings Volume 2700, (1996) https://doi.org/10.1117/12.239673

KEYWORDS: Raman spectroscopy, Bioalcohols, Luminescence, Raman scattering, Dye lasers, Binary data, Distortion, Laser scattering, Ions, Nd:YAG lasers

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High-Q morphology-dependent resonances (MDR's) in microdroplets provide optical feedback for nonlinear processes such as stimulated Raman scattering (SRS). The SRS signal from weaker gain modes or from the minority species in a binary mixture droplet is small, because of depletion of the pump beam by the strongest-gain Raman mode. We present an effective- average Raman gain formula and discuss the factors that contribute to the enhancement of SRS intensity. Spatial overlap between pump wave and SRS wave is an important factor in determining the SRS intensity. We have observed that in a binary mixture microdroplet, the SRS of the majority species is more efficient (because of good spatial overlap) in pumping the minority species than the input laser itself. Laser-induced distortion can couple light efficiently into a droplet. We have used a variable number (3 - 6) of mode-locked 100-psec laser pulses focused on the droplet rim. The SRS emission from a minority species increases as the number of input pulses is increased, because cumulative laser-induced surface distortion couples more energy into the droplet. SRS signal at the Stokes shift of a weaker gain mode or of the mode of a minority species can be enhanced by seeding light at the SRS wavelengths. The seed signal is obtained from the fluorescence of a dye added to the microdroplet or from external coupling of light into the droplet. A lasing dye (Rhodamine 6G) is added to pure ethanol droplet. By using an excimer-pumped tunable dye laser as the excitation source, the weaker gain C-C-O mode (882 cm^-1 Stokes shift) of ethanol is overlapped spectrally with the fluorescence and lasing of R6G. The SRS signal of the C-C-O mode is enhanced, because (1) the fluorescence of R6G at the SRS wavelength adds to the spontaneous SRS emission and (2) the gain from population inversion adds to the Raman gain. We have also observed enhanced SRS emission from a minority species (benzene) in dodecane by using internal dye seeding. We externally seeded ethanol SRS (2928 cm^-1) in a binary mixture (12% ethanol and 88% water) microdroplet by using a frequency-doubled Nd-YAG pumped tunable dye laser. A large (factor of 45) enhancement in the ethanol SRS (integrated over 100 shots of a 10-ns laser) has been observed.

Conference Committee Involvement (5)

Metro and Data Center Optical Networks and Short-Reach Links

30 January 2018 | San Francisco, California, United States

Next-Generation Optical Networks for Data Centers and Short-Reach Links IV

31 January 2017 | San Francisco, California, United States

Next-Generation Optical Networks for Data Centers and Short-Reach Links III

16 February 2016 | San Francisco, California, United States

Next-Generation Optical Networks for Data Centers and Short-Reach Links II

10 February 2015 | San Francisco, California, United States

Next-Generation Optical Networks for Data Centers and Short-Reach Links

4 February 2014 | San Francisco, California, United States

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