Events Calendar
New optical sources for physics and spectroscopy based on an old trick of atomic physics
Tuesday October 25, 2016
| 2:00 pm
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Presenter: | Dr. Jeffrey Moses, Assistant Professor, Cornell University |
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| Series: | OSE Seminars | |
| Abstract: | From strong-field optical physics to nonlinear phononics and femtosecond-resolved optical spectroscopy, developing fields of optical physics are making demands for coherent light sources of greater bandwidth, greater intensity, and in new ranges of the electromagnetic spectrum. Yet, lasers and nonlinear optical sources of coherent light have been limited by the same old problems of narrow gain bandwidth and a trade-off between bandwidth and gain. Here we show how an old trick of atomic physics, rapid adiabatic passage, can get around these old limitations. We'll discuss how nonlinear optical frequency conversion via three-wave mixing can be described by the same equations that govern spin flips in Nuclear Magnetic Resonance and the coupling of ground and excited quantum states through an electromagnetic field. We'll then continue to show how the conversion-backconversion cycles typical of nonlinear optical frequency conversion can be avoided by use of quasi-phase matching with an aperiodic poling period. Under these conditions, frequency conversion is mathematically analogous to rapid adiabatic passage, and light can be converted efficiently and without backconversion. Moreoever, as we have demonstrated experimentally, a properly designed poled nonlinear crystal can generate octaves of bandwidth in the mid-infrared with arbitrarily shaped amplitude and phase. Due to the robust phase and amplitude transfer of the conversion process, this multi-octave shaping capability is enabled by use of an ordinary pulse shaper prior to conversion. | |
| Location: | Room 146, Center for High Tech Materials | |
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