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


                        Mar. Meeting

Date:  Thursday, 15 Mar. 2001
Time:  7:00 PM refreshments, 7:30 PM talk
Place: National Institute of Standards and Technology
       325 Broadway, Boulder, CO
       Room 1107


Title: Ultrafast Solid-State Lasers

       Dr. Ursula Keller
       Ultrafast Laser Physics
       Institute of Quantum Electronics
       Physics Department
       Swiss Federal Institute of Technology
       keller@iqe.phys.ethz.ch

       IEEE/LEOS Distinguished Lecturer


Abstract:

Today's ultrafast all-solid-state lasers continue to 
demonstrate unsurpassed performance in terms of pulse 
duration, pulse repetition rates, average power and 
wavelength range.  Optical pulses in the 5-femtosecond range 
are produced with Ti:sapphire lasers using Kerr lens 
modelocking (KLM) with chirped mirrors for higher order 
dispersion compensation.  However, the technique of KLM, 
successful with Ti:sapphire, has not performed so well in 
directly diode-pumped lasers.  Semiconductor saturable 
absorber mirrors (SESAMs) were a breakthrough resulting in 
the first demonstration of self-starting and stable passive 
mode locking of diode-pumped solid-state lasers with an 
intracavity saturable absorber in 1992.  Earlier attempts of 
intracavity saturable absorbers in solid-state lasers 
produced at best stable Q-switched modelocked pulses, where 
the pico- or femtosecond modelocked pulses are inside much 
longer Q-switched pulse envelopes.  The design freedom of 
SESAMs has allowed us systematically to investigate the 
stability regime of passive cw modelocking with an improved 
understanding and modeling of Q-switching instabilities.  
Simple design guidelines allowed us to push the frontiers of 
ultrafast solid-state lasers in terms of average power and 
pulse repetition rates.  Presently, micro-Joule-level pulse 
energies in both the pico- and femtosecond regime are 
available directly from compact solid-state lasers without 
any cavity dumping or further pulse amplification.  In 
addition, the pulse repetition rate has been pushed to about 
80 GHz using quasi-monolithic miniature Nd:TVO4 laser 
cavities.  The goal of this talk is to give a tutorial 
overview of these exciting developments during the last ten 
years.


Biography:

Ursula Keller was born in Zug, Switzerland, in June 1959.  
She received the "Diplom" in Physics from the Federal 
Institute of Technology (ETH) Zurich, Switzerland in 1984.  
From late 1984 to 1985 she worked on optical bistability at 
Heriot-Watt University, Edinburgh, Scotland.  She then moved 
to Stanford University, Stanford, CA and earned her M.S. and 
Ph.D. degree in Applied Physics in 1987 and 1989, 
respectively.  For her first year at Stanford she held a 
Fulbright Fellowship and for the following year she was an 
IBM Predoctoral Fellow.  Her Ph.D. research was in optical 
probing of charge and voltage in GaAs integrated circuits and 
in low-noise ultrafast laser systems.

In 1989, she became a Member of Technical Staff (MTS) at AT&T 
Bell Laboratories, Holmdel, NJ, where she conducted research 
on photonic switching, ultrafast laser systems, and 
semiconductor spectroscopy.  In March 1993 she was appointed 
an Associate Professor and in Octorber 1997 she became a Full 
Professor in the Physics Department at the Swiss Federal 
Institute of Technology (ETH) in Zurich, Switzerland.  Her 
current research interests are in ultrafast lasers, 
attosecond science, spectroscopy, local probes and novel 
devies for applications in optical information processing, 
communication and medicine.  She has published more than 150 
journal papers and 4 book chapters and she holds or applied 
for ten patents.  In 1998, she received the Carl Zeiss 
Research Award for her pioneering work in novel modelocking 
and Q-switching techniques using semiconductor saturable 
absorber mirrors (SESAMs).  In 2000 she was selected to be 
one of the LEOS Distinguished Lecturers for 2000-01.

Prof. Keller is a member of the Optical Society of America 
(OSA), the Institute of Electrical and Electronics Engineers 
(IEEE), the European Physical Society (EPS), the Swiss 
Physical Society (SPS), the Swiss Academy of Technical 
Sciences (SATW) and the Swiss Academy of Sciences.