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
CREOL Room 102
Jürgen Jahns
FernUniversitat in Hagen, Germany
Abstract:
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.
Biography:
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
407-882-3326
besaleh AT creol . ucf . edu
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