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Full-Text Articles in Physical Sciences and Mathematics
Phase Control In Atomic Coherence, Utsab Khadka
Phase Control In Atomic Coherence, Utsab Khadka
Graduate Theses and Dissertations
In this thesis, atomic coherence is used to enhance nonlinear optical processes in multi-level atoms. The multi-photon transitions are driven resonantly, and at the same time without absorptive losses, by using electromagnetically induced transparency (EIT), thereby allowing the study of χ(3) and χ(5) nonlinearities using weak driving fields. The coherently modified probe beam(s) and the atom-radiated signal fields arising from four- and six- wave- mixing (FWM and SWM) processes are measured in the spectral, temporal and spatial domains.
In a three-level ladder-type atomic system, multiple peaks having spectral asymmetries are observed in the EIT window as well as …
Third Order Nonlinearity Of Organic Molecules, Honghua Hu
Third Order Nonlinearity Of Organic Molecules, Honghua Hu
Electronic Theses and Dissertations
The main goal of this dissertation is to investigate the third-order nonlinearity of organic molecules. This topic contains two aspects: two-photon absorption (2PA) and nonlinear refraction (NLR), which are associated with the imaginary and real part of the third-order nonlinearity (χ (3)) of the material, respectively. With the optical properties tailored through meticulous molecular structure engineering, organic molecules are promising candidates to exhibit large third-order nonlinearities. Both linear (absorption, fluorescence, fluorescence excitation anisotropy) and nonlinear (Z-scan, two-photon fluorescence, pump-probe) techniques are described and utilized to fully characterize the spectroscopic properties of organic molecules in solution or solid-state form. These properties …