Nonlinear Optical Spectroscopy: Absorption and Refraction

Seminar by
Dr. Eric Van Stryland
Dean, College of Optics and Photonics: CREOL & FPCE
University of Central Florida
Orlando, FL 32816-2700

Abstract: We have been developing a number of spectroscopic methods for accurately measuring the nonlinear absorption spectrum along with the dispersion of the nonlinear refraction of optical materials from semiconductors to organic dyes. These methods include the 'standard' Z-scan, femtosecond pump/continuum probe spectroscopy, and more recently a femtosecond white-light continuum Z-scan. The Z-scan is a simple method that can simultaneously measure both the sign and magnitude of the nonlinear absorption and nonlinear refraction with interferometric sensitivity. The Z-scan techniques yield the frequency degenerate spectra (equal photon energies) while the pump/probe method gives the nondegenerate nonlinearities which allows for nonlinear Kramers-Kronig relations between refraction and absorption (even though Kramers-Kronig relations normally come from linear dispersion theory). We will show a variety of examples of spectra along with some scaling laws for semiconductors.

Bio: ERIC W. VAN STRYLAND, Prof. of Optics, Dean, College of Optics & Photonics

Eric Van Stryland received the Physics PhD degree in 1976, from the University of Arizona, Optical Sciences Center, Tucson, AZ, where he worked on optical coherent transients and photon counting statistics. He worked in the areas of femtosecond pulse production, multiphoton absorption in solids, and laser induced damage at the Center for Laser Studies at the University of Southern California. He joined the physics department at the University of North Texas in l978 helping to form the Center for Applied Quantum Electronics. In l987 he joined the newly formed CREOL (Center for Research and Education in Optics and Lasers) at the University of Central Florida where he was Professor of Physics and Electrical and Computer Engineering. NSF has funded him for the past 25 years and he has been performing research for the DoD. His current research interests are in the characterization of the nonlinear optical properties of materials and their temporal response as well as the applications of these nonlinear materials properties for sensor protection, switching, beam control etc. He helped develop the Z-scan technique with Mansoor Sheik-Bahae with whom he also established the methodology for apply Kramers-Kronig relations to ultrafast nonlinearities. He is a fellow of the Optical Society of America, a member of their Board of Directors and co-chair of the Science and Engineering Council, and was elected vice president in 2003 (will become President in 2006 and is currently President Elect). He also served as a topical editor for Optics Letters. He is a senior member of the Laser Institute of America and a former board member, a senior member of IEEE LEOS and a member of the SPIE, and MRS. He has graduated 22 Ph.D.'s and published well in excess of 100 journal articles. He has been Director of the School of Optics/CREOL since July 1999 and became Dean of the College of Optics and Photonics in 2004.