ROCKY MOUNTAIN SECTION OPTICAL SOCIETY OF AMERICA
                              &
           IEEE LASERS AND ELECTROOPTICS SOCIETY


                        Jan. Meeting

Date:  Thursday, 16 Jan. 2003
Time:  7 PM refreshments, 7:30 PM talk
Place: National Center for Atmospheric Research
       Center Green Campus
       Center Green Drive, Boulder, CO


Title: Imaging with Terahertz Waves

       Dr. Daniel Mittleman
       Electrical & Computer Engineering, MS-366
       Rice University
       6100 Main St.
       Houston, TX 77005
       (713)348-5452
       daniel@rice.edu
       www-ece.rice.edu/~daniel/Mittleman.html 


Abstract:

Traditionally, the region of the spectrum between 100 
gigahertz and 10 terahertz  (corresponding to the wavelength 
range 30 microns - 3 mm) has been among the least  explored, 
due in part to the difficulties associated with efficient 
generation and detection  schemes.  However, the recent 
development of a number of new experimental techniques has 
sparked a growing interest in the use of terahertz radiation 
for imaging, spectroscopy, and a  variety of commercial 
applications.  This talk presents an overview of this rapidly 
developing field, and a description of a few of the unique 
imaging capabilities of the "T-ray"  imaging system.  For 
example, by combining interferometry with the coherent 
detection  capability of time-domain spectroscopy, it is 
possible to form time-of-flight images with a  depth 
resolution well below the limit imposed by the coherence 
length of the radiation.  The  use of broadband radiation for 
imaging also requires a rethinking of such concepts as the 
Fresnel zone, which is typically defined only at a single 
frequency.  Such considerations have  a bearing on the 
lateral resolution in a tomographic image, and have 
implications in fields as  diverse as biomedical imaging and 
geophysical prospecting.


Biography:

Dr. Mittleman received his B.S. in physics from the 
Massachusetts Institute of Technology  in 1988. He then went 
on to the University of California, Berkeley, where he joined 
the  research group of Charles Shank. His primary research 
involved the spectroscopy of  semiconductor nanocrystals 
using laser pulses with durations of less than 20 
femtoseconds,  at wavelengths from 480 nm to 670 nm. These 
experiments were performed in collaboration  with the 
Alivisatos group in the Chemistry Department at Berkeley, and 
were carried out at the Lawrence Berkeley National 
Laboratory. Dr. Mittleman received his M.S. in 1990, and  his 
Ph.D. in 1994, both in physics. 

Dr. Mittleman then joined the research group of Dr. Richard 
Freeman, as a Postdoctoral  Member of the Technical Staff at 
AT&T Bell Laboratories. While there, he pursued research into 
high harmonic generation in noble gases using a 100 
femtosecond, 1 terawatt laser  system. When Dr. Freeman left 
Bell Labs in early 1995, Dr. Mittleman began working with Dr. 
Martin Nuss, who had just pioneered the use of THz time-
domain spectroscopy for  imaging. Dr. Mittleman's work in 
this laboratory included the non-contact characterization of 
doped semiconductor wafers using the THz Hall effect, the 
construction of a THz imaging  system in a reflection 
geometry for use in "T-Ray Tomography" measurements, and the 
THz  spectroscopy of inverse micelles of water in heptane. 
During this time, AT&T split into  three companies, and most 
of Bell Labs became part of one of the three pieces, Lucent 
Technologies. Dr. Mittleman joined the ECE Department at 
RiceUniversity in September  1996.    His current research 
involves imaging and sensing with terahertz radiation, with a 
particular focus on the use of terahertz pulses to study 
light scattering and photon diffusion.   In 2002-2003, Dr. 
Mittleman is a Distinguished Lecturer for the IEEE Lasers and 
Electro-Optics Society.