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OSA Student Chapter Meeting

SPEAKER:Sean O'Connor
TITLE: Thermally Tunable Microlenses
Wavefront shaping (WFS) techniques involve the optimization of a pulse's wavefront by modulating the phase or amplitude at different points along the incident light's spatial profile. These techniques have been useful for astronomy and microscopy due to their improvements in imaging. WFS has also been used for focusing in or past a turbid medium as well as delivering optical information beyond a scattering medium. Spatial light modulators (SLM) as well as deformable mirrors have been widely used to perform WFS. However, SLMs have drawbacks of being polarization and wavelength dependent while deformable mirrors have limitations at the microscale. Recently, researchers from Spain and France have developed a thermally tunable lens for WFS, which they call the SmartLens, where they change the local index of refraction at points in a polymer with electrical heaters. For the OSA News, I will present their recent publication on their SmartLens, and I will compare it to conventional WFS equipment such as SLMs.

SPEAKER: Christopher Marble
TITLE: Optical Activity of Hyper-Raman Scattering
The optical activity of Raman scattering provides insight into the absolute configuration and conformation of chiral molecules. Applications of Raman optical activity (ROA) is limited by long integration times due to the relatively low intensity differences (typically 10-3 to 10-4) of the Raman scattered light for different incident polarizations. This limitation has led to coherent techniques such as stimulated ROA, CARS-ROA (Coherent Anti-Stokes Raman Scattering) and ROACH (ROA Coherent Heterodyning) to increase photon count rates. Instead of utilizing a coherent process to enhance ROA, we instead apply ROA techniques to hyper-Raman scattering using incident circularly polarized light and a right-angle scattering geometry. We, to the best of our knowledge, for the first time observe hyper-Raman optical activity (HROA) and report progress in measuring the HORA spectra of biologically relevant molecules such as tartaric acid.

Thursday, September 5 2019
IQSE 578, 12:30
Mitchell Physics Building

Department of Physics and Astronomy
Institute for Quantum Science and Engineering
Texas A&M University

(Pizza lunch as usual. Newcomers welcome!)

Host: Sean O'Connor