seal-color.gif University of Michigan
Department of Electrical Engineering and Computer Science

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Herbert Winful

Arthur F. Thurnau Professor
ECE Division
Optical Sciences Laboratory
Also:
Professor, Applied Physics
CUOS Associate Director for Education

1114 EECS
1301 Beal Avenue
Ann Arbor, MI 48109-2122

PHONE:
(734) 647-1804
FAX: (734) 647-2718
EMAIL: winful@eecs.umich.edu

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Research Projects:

Research Overview:

Advances in ultrafast optical technology have made possible the generation of single-cycle electromagnetic pulses whose bandwidths are comparable to the center frequency. Because different frequency components diffract differently, such pulses undergo significant temporal reshaping even when they propagate through free space. Because they contain only one cycle they cannot be properly described by the slowly varying envelope approximation. We have obtained exact solutions of Maxwell's equations that correctly describe the spatiotemporal evolution of focused single-cycle electromagnetic pulses. These solutions show how the Gouy phase shift leads to polarity reversals and temporal reshaping as the pulses propagate. The results have implications for both terahertz pulses and few-cycle femtosecond laser pulses. We are currently investigating the nonlinear interactions of these single-cycle pulses.
 
A second area of research involves novel grating structures in semiconductor lasers. We are investigating two-dimensional distributed feedback lasers and their potential for high power, single longitudinal and lateral mode operation. We are also studying Bragg amplifiers for wavelength conversion applications.
 

Recent Courses Taught:

Publications:

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