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|Title:||ALS-CXRO Seminar | Ernie Glover|
|When:||02/ 6/2013 3:00 PM - 4:00 PM|
|Description:||ALS-CXRO Seminar Series|
Wed, February 6, 2013
Peter Fischer/Jinghua Guo
X-ray and optical wave mixing
Though light-matter interactions are broadly important and have been heavily studied, their microscopic details are often poorly understood and have, to date, not been directly measurable. X-ray and optical wave mixing was proposed nearly a half century ago as an atomic-scale probe of a material's optical response. This x-ray scattering process is similar to conventional x-ray scattering with the distinction that it probes optically polarized (valence) charge. Accordingly, one directly measures the optically induced charges and associated microscopic fields that arise in an illuminated material. I will discuss x-ray/optical sum frequency generation (x/o SFG); the physical mechanism dominating the nonlinearity, our experiments using single crystal diamond at the Linac Coherent Light Source, and what we have learned about microscopic optical interactions in covalent semiconductors. Finally, I will briefly speculate on new ways to probe materials using x/o SFG.