High brighteness table-top extreme ultraviolet (EUV) sources
Sources of EUV and soft X-ray radiation have normally been available only at large scale national facilities. Since the 1990s, low repetition rate (kHz), amplified femtosecond Ti:Sapphire laser systems have been employed to generate both EUV radiation and soft X-rays via high harmonic generation (HHG) in noble gases. While these table-top sources have found application in many scientific labs, a key shortcoming preventing their more widespread use and application is the low photon flux (or brightness). This condition is due to the extremely low inefficiency of the HHG conversion. In this project we are following the pioneering initial work of Ye et al in which HHG was demonstrated within a phase-stabilized passive enhancement (buildup) cavity. This novel approach offers a route toward much higher photon flux along with production of EUV pulses at 50 to 100 MHz in repetition rate and superior amplitude noise. All of these characteristics make this approach particularly attractive for use in EUV spectroscopy applications. Specifically, we are working to maximize the photon flux while optimizing the spectral coverage and properties with an end goal of using the source in Angle Resolved Photo emission Spectroscopy (ARPES) experiments. We are also working with Prof. Ruth Signorell to use this source as a metrology tool for nanoparticles in aerosols.
Optical frequency metrology with fiber laser based femtosecond frequency combs
In collaboration with the IMNS group at NRC Ottawa, we have developed a femtosecond frequency comb produced by a mode-locked fiber laser centered at 1550 nm. Both relative and self-referenced measurements are being compared with femtosecond frequency combs generated by conventional solid states lasers. In addition, the fs fiber laser comb is being employed to map the acetylene absorption atlas in the 1550 nm region and as clockwork to evaluate NRC's Sr+ ion frequency standard and the upcoming Sr neutral atom standard against a Cs fountain clock.
Spectroscopy with THz Frequency combs
In a new research effort we are extending femtosecond frequency combs into the THz and far-infrared electromagnetic spectral region for precision spectroscopy applications. This approach offers substantially higher precision than is currently available while still enjoying rapid (<1 sec) acquisition, high sensitivity, and broad band coverage.
Femtosecond lasers + cold atoms/molecules
In collaboration with the group of Kirk Madison, we are pursuing a research program of combining stabilized fs frequency combs with studies of cold atoms and molecules. Toward this end, we have developed a tunable, single mode optical frequency synthesizer capable of tuning from 720 to 810 nm with a 100 kHz uncertainity. This synthesier is now being utilized to perform photoassociation spectroscopy of cold Rb-Li atomic gases. Some of our long term goals include studying cold collisions between Rb and Li atoms andformation of bound, vibration-cold Rb2 Li2 and Rb-Li dimers