University of Waterloo
200 University Avenue West
Waterloo, Ontario, Canada N2L 3G1
Phone: (519) 888-4567 ext 32215
Fax: (519) 746-8115
Office: PHY 257
Phone: (519) 888-4567 ext. 32724
Website: Ultrafast Laser Group
We are investigating the nonlinear optical technique of multi-frequency Raman generation, (MRG). In MRG, a large number of Raman orders spanning from infrared to ultraviolet are generated by pumping a molecular gas with two strong pumps having a frequency separation matching the vibrational or rotational frequency. Waterloo's ultrafast laser group has developed a high intensity, two-colour, Ti:sapphire laser, which is an ideal source for studying MRG. This coherent nonlinear interaction allows the Raman orders to be phased together to generate a train of very short pulses, approaching single femtosecond durations, which can be used to make "freeze frame" movies of molecular motion.
The spectral region from 6 to 25µm is known as the "molecular fingerprint region" because almost every molecule has a distinctive signature in its absorption spectra at these wavelengths. Along with applications in environmental monitoring and medical applications, this spectral region is becoming increasingly important for trace gas detection of explosives. At Waterloo, we are developing a two-colour, short pulse fiber laser system to generate mid-infrared wavelengths across the fingerprint region by difference frequency mixing the two laser outputs in a nonlinear crystal. Currently we have generated sub-picosecond mid-infrared pulses with over 1mW of average power with wavelengths tunable from 16 to 20 µm.
In a collaborative project with Prof. Melanie Campbell and Prof. Joe Sanderson, we are studying the role of self-focusing and multi-photon ionization on micro-cavity bubble formation within the crystalline lens. Micromachining of the crystalline lens of the eye has become an active area of research to determine if the elasticity of the lens can be improved by creating microbubbles within the lens to possible cure the condition of Presbyopia.