Hyperspectral coherent light sources and
Ultrafast studies of molecules and few-body quantum systems at MIT
I'm a Research Scientist at MIT in the Research Laboratory of Electronics, a contracted Principal Investigator for the Air Force Office of Scientific Research, and a member of the Ultrafast Optics and X-rays Group headed by Prof. Franz Kaertner. Our work focuses on the development of hyperspectral light-pulse tools that can capture "ultrafast phenomena" (events so brief as to be barely detectable by state-of-the-art technology) in real time.
I'm currently leading a project in
attosecond molecular physics with an aim to probe fundamental correlations between electrons and protons in the smallest of molecules. We are developing tools involving the simultaneous use of extreme ultraviolet rays with sub-femtosecond duration (<10-15 sec.) and intense mid-infrared light pulses lasting only a few optical cycles to precisely control the phase between molecular vibrations and synchronized optical fields. With these tools we can learn about the ways molecules dissociate, endeavor to control these processes in real time, and explore the physics of few-body correlations in materials.
Researchers in our field have witnessed a bewilderingly fast development of new optical tools over the past decade, making it an exciting period for us! Through the interaction of intense laser light with various materials, energetic light pulses with frequencies from the soft-X-ray to THz can be produced, coherent with the driving laser. For the first time, intense near-infrared pulses have been engineered to last only a single cycle of an electromagnetic wave. Our research team in Prof. Kaertner's labs at MIT was one of the first to accomplish this [Nature Photonics 5, 475 (2011)].
Graphic from Nature Photonics 5, 475 (2011).
As mentioned above, we are often interested in applying new optical tools to old problems of atomic and molecular physics. But sometimes a kind of converse is possible, as we have found that we can apply some traditional methods for controlling atomic populations, should as rapid adiabatic passage, to the control of nonlinear optics and frequency conversion! In a recent research collaboration with Dr. Haim Suchowski at UC Berkeley, we were able to convert a 110-nm band from the visible segment of a Ti:sapphire laser oscillator's spectrum to a 900-nm band in the near-to-mid infrared portion of the electromagnetic spectrum (making up almost a full octave of bandwidth), with full photon number conversion efficiency. The process, adiabatic difference frequency generation, was shown to obey the Landau-Zener prediction of conversion efficiency for an adiabatic conversion process. We are currently applying the technique to mid-infrared light pulse generation, funded by an Air Force Young Investigator grant.
Graphic from Optics Letters 37, 1589 (2012).
If you're interested in learning more, feel free to contact me at j_moses (at) mit.edu. From these pages, you can also link to my CV and list of publications.