Prof  Ursula Keller (2000/2001 IEEE Distinguished Lecturer)

PROGRAMME

Physics Room 113:

2:00 - 2:30pm    Registration, Coffee and poster hanging

Lecture Theatre 3:

2:30 - 2:50pm   "120 W Nd: YAG planar waveguide laser face pumped by diode bars"
                           Graham Friel, Heriot-Watt University

2:50 - 3:10pm   "A Parametric Study of Single Pulse Laser  Drilling of Aluminium and Titanium"
                           William Rodden, Heriot-Watt University

3:10 - 3:30pm   "2.1 THz Modelocking Rate From Monolithic Compound-Cavity Laser Diodes"
                          Dan Yanson, University of Glasgow

3:30 - 3:45pm   "Modelocking of an Yb:YCOB laser using an ion-implanted saturable Bragg reflector"
                           Gareth Valentine, Strathclyde University

3:45 - 4:00pm   "Ultrashort-pulse Lasers: From Lab to Home"
                           John-Mark Hopkins, St Andrews University

4:00 - 4:30pm   "Coatings, materials and devices enabling DWDM"
                           Frank Tooley, CTO, THz Photonics

Physics Room 113:

4:30-6:00pm     Poster Session (see below) , Cheese and Wine, and Table-Top Exhibition by Elliott Scientific Ltd.

Lecture Theatre 3:

6:00-7:00pm    KEYNOTE ADDRESS: (see below)

7.00pm           Presentation of Student Poster Prize and Close

Today's ultrafast all-solid-state lasers continue to demonstrate unsurpassed performances in terms of pulse duration, pulse repetition rates, average power and wavelength range:  optical pulses in the 5-femtosecond range are produced by a variety of methods.  Although different in technical detail, each method relies on the same three key components:  spectral broadening due to the nonlinear optical Kerr effect, dispersion control, and ultrabroadband amplification. Pulses as short as 5.8 fs have been generated directly from a Ti:sapphire laser without any external pulse compression.  The shortest pulses generated to date all rely on chirped mirrors for dispersion compensation.  A major limitation in chirped mirror design arises due to interference between light reflected at different penetration depths inside the mirror structure. This results in residual oscillations in the group delay dispersion (GDD) which ultimately limits pulse shortening.  Unfortunately, there is always a trade-off between GDD-oscillations and reflection bandwidth.  The double-chirped mirror technique (DCM) reduced GDD oscillations and resulted in the sub-6-fs pulses.  Novel DCM designs result in a sufficiently large reflection bandwith that could, in principle, support
4-fs pulses.  The technique of Kerr lens modelocking (KLM), successful with Ti:sapphire, has not performed so well in directly diode-pumped lasers.  Early intracavity saturable absorbers produced at best stable Q-switched modelocked pulses, where the pico- or femtosecond modelocked pulses are inside much longer Q-switched pulse envelopes.
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.  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.  Presently the frontiers in average output power are diode-pumped Nd:YAG (27 W average output power and 19 ps pulse duration), Yb:YAG (16 W and 730 fs) and Nd:glass (1.4 W, 275 fs) lasers.  This basically means that µJ-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.  The frontiers in pulse repetition rate has been pushed to nearly 80 GHz using quasi-monolithic miniature Nd:YVO4 laser cavities.

Biography

URSULA KELLER is a full professor of experimental physics and head of the Ultrafast Laser Physics Laboratory at the Swiss Federal Institute of Technology in Zürich (ETH).

Ursula Keller was born in Zug, Switzerland, in June 1959. She received the "Diplom" in physics from the Federal Institute of Technology (ETH) Zürich, Switzerland in 1984. From late 1984 to 1985 she received an ETH research fellowship to work on optical bistability at Heriot-Watt University, Edinburgh, Scotland. She then continued to earn her M.S. and Ph.D. degree in Applied Physics from Stanford University, Stanford, CA in 1987 and 1989, respectively. 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 joined AT&T Bell Laboratories, Holmdel, NJ, as a Member of Technical Staff where she conducted research on photonic switching, ultrafast laser systems, and semiconductor spectroscopy. In March 1993, she became an associate Professor, and since October 1997 she has been a full Professor in the Physics Department at the Swiss Federal Institute of Technology (ETH) in Zürich Switzerland. Her current research interests are in diode-pumped solid-state lasers, ultrafast lasers using semiconductor saturable absorber mirrors, time-resolved spectroscopy, ultrafast local probes and novel devices for applications in optical information processing, communication and medicine. She published more than 130 journal papers, four book chapter (two in press) and holds 6 and filed for another 5 patents.

POSTERS
 

P1.  "Compact, Low-Threshold Femtosecond Lasers"  Ben Agate, University of St Andrews

P2.  "Dramatic spectral narrowing of a gain-switched diode laser in a weak non-resonant external cavity", D. J. L. Birkin, E. U. Rafailov, E. Avrutin, W. Sibbett, University of St Andrews.

P3. "Theory of the modulation of optical nonlinearities in semiconductor superlattices using disordering" D.C.Hutchings, University of Glasgow

P4. "Polarisation stability of Kerr optical solitons: a comparison of birefringent fibre and semiconductor waveguide",  D.C.Hutchings and J.M.Arnold,  University of Glasgow

P5. "Quasi-phase-matching of optical parametric processes in semiconductor waveguides" D.C.Hutchings, A.Saher-Helmy, T.C.Kleckner, K.Zeaiter, J.H.Marsh, J.M.Arnold, J.S.Aitchison, C.T.A.Brown, K.Moutzouris and M.Ebrahimzadeh, University of Glasgow and University of St Andrews
 

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Last update by AM: 10/10/2000