Non-degenerate two photon absorption spectra of Si nanocrystallites

Non-degenerate Two Photon Absorption Spectra of Si Nanocrystallites

The two-photon absorption (TPA) spectrum is an important optical property of semiconductors. It brings valuable information complementary to the one-photon absorption spectrum, gives the limits to the optical transparency of materials, and causes laserinduced damages. Recently, the TPA spectrum of direct-gap nanocrystallites was calculated by Cotter et al. [1] by using the effective-mass approx...

Two-photon absorption spectra of carotenoids compounds

Sensitive mid-infrared detection in wide-bandgap semiconductors using extreme non-degenerate two-photon absorption

Identifying strong and fast nonlinearities for today’s photonic applications is an ongoing effort1. Materials2–5 and devices6–9 are typically sought to achieve increasing nonlinear interactions. We report large enhancement of two-photon absorption through intrinsic resonances using extremely non-degenerate photon pairs. We experimentally demonstrate two-photon absorption enhancements by factors...

Non-Condon Effects in the One- and Two-Photon Absorption Spectra of the Green Fluorescent Protein

We report calculations of one and two photon absorption (OPA and TPA, respectively) spectra of the green fluorescent protein (GFP) chromophore using the doubleharmonic parallel-mode approximation and including explicit dependence of the electronic transition moments on nuclear geometry. The non-Condon effects are found to be more significant for TPA resulting in a different shape of the spectra...

Non equilibrium spectra of degenerate relic neutrinos

We calculate the exact kinetic evolution of cosmic neutrinos during the epoch previous to Big Bang Nucleosynthesis, in the case when a large neutrino asymmetry exists. By solving numerically the Boltzmann kinetic equations for the neutrino distribution functions, we find the momentum-dependent corrections to the equilibrium spectrum of neutrinos and discuss their phenomenological implications. ...