Tuesday, January 7, 2014

Distinguished Seminar Series: "Diffractive optics for short wavelengths and short pulses" by Jürgen Jahns 2.17.14/11:00am-12:00pm/ CREOL 102

Distinguished Seminar Series: "Diffractive optics for short wavelengths and short pulses" by Jürgen Jahns

Monday, February 17, 2014 11:00 AM to 12:00 PM
CREOL Room 102

 Jürgen Jahns
FernUniversitat in Hagen, Germany

Over the past 20 years, diffractive optics has developed from an area of active research to a mature field with numerous commerical applications. And yet, there exists still a potential for novel applications and thus interesting research topics. Here, I will discuss two topics: the first is imaging at EUV and X-ray wavelengths using diffractive lenses, the second is the spatio-temporal filtering of ultrashort pulses using diffractive optics.
Focusing and imaging of EUV and x-ray radiation (i.e., at wavelengths from approximately 0.1 - 100 nm) has many applications, for example, in astronomy and the life sciences. However, at these wavelengths, the use of conventional refractive lenses is not practical, since all materials are strongly absorbing and the values of the refractive index are very close to one. As an alternative to using refraction, a one may consider a diffractive implementation. Special diffractive lenses, such as the “photon sieve” and “azimuthally modulated Fresnel zone plate” have been demonstrated in recent years. Here, the concepts behind these elements will be described and a diffraction-theoretical analysis will be presented.
 The second topic to be addressed is the use of microoptical elements for the shaping and filtering of ultrashort optical pulses. Shaping in the spatial domain includes, for example, the generation of vortex beams. A diffractive implementation of a vortex beam is achieved by a so-called spiral axicon. Using diffraction, however, leads to strong chromatic dispersion which is a problem for ultrashort pulses. Here, a refractive-diffractive dispersion compensation is presented.
 Finally, we show the fabrication of a highly precise micro-retroreflector array by the LIGA technology and discuss the possibility of using it as a time-domain filter for femtosecond pulses.

Jurgen Jahns got his diploma and doctorate in physics from the University of Erlangen-Nuremberg, Germany, in 1978 and 1982, respectively. He worked at Siemens, Munich, Germany, and at AT&T Bell Laboratories, Holmdel, New Jersey, before becoming full professor and chair of optical information technology at the FernUniversitat in Hagen, Germany, in 1994. He has co-authored more than 95 journal articles and several books on microoptics and photonics. Jahns is a Fellow of OSA and SPIE and a member of DGaO (German Society of Applied Optics), EOS, and IEEE.

For additional information:
Dr. Bahaa E. A. Saleh
Dean & Director, Professor of Optics
besaleh @ creol . ucf . edu

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