Femtosecond transient absorption pump-probe spectroscopy has been used to study the third- and fifth-order nonlinear susceptibility of UV-grade fused silica. Theoretical simulations support the experimental evidence of interference between the third- and fifth-order contributions to the signal. Approximate values of the second-order nonlinear refractive index n(4) and of the three-photon absorption coefficient gamma are obtained.
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http://dx.doi.org/10.1364/ol.26.000896 | DOI Listing |
Nat Commun
January 2025
Department of Basic Science, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro, Tokyo, 153-8902, Japan.
Coherent Raman scattering spectroscopies have been established as a powerful tool for investigating molecular systems with high chemical specificity. The existing coherent Raman scattering techniques detect only Raman active modes, which are a part of the whole molecular vibrations. Here, we report the first observation of coherent anti-Stokes hyper-Raman scattering (CAHRS) spectroscopy, which allows measuring hyper-Raman active vibrations at high speed.
View Article and Find Full Text PDFJ Chem Phys
September 2024
Institute of Chemical Physics, Physics Faculty, Vilnius University, Sauletekio ave. 9-III, Vilnius, Lithuania.
Two-dimensional electronic spectroscopy (2DES) is a powerful spectroscopic tool that allows us to study the dynamics of excited states. Exciton-exciton annihilation is at least a fifth order process, which corresponds to intrachromophoric internal conversion from the double-excited high-energy chromophoric state into the single-excited state of the same chromophore. At high excitation intensities, this effect becomes apparent in standard 2DES and can be inspected via high order nK1⃗-nK2⃗+K3⃗ nonlinear processes.
View Article and Find Full Text PDFHeliyon
August 2024
Department of Mathematics, School of Advanced Sciences, Vellore Institute of Technology, Chennai, 600127, Tamilnadu, India.
Present study investigates influence of Soret-Dufour effects on MHD unsteady flow of a tetra-hybrid nanofluid (AlO, Cu, SiO and TiO with base fluid water) within non-Darcy porous stretching cylinder. Additionally, chemical reaction, activation energy, and heat generation are considered. This research contributes to the understanding of how these nanofluids can optimize heat and mass transfer process in applications such as advanced cooling systems, solar collectors, biomedical devices, and chemical reactors.
View Article and Find Full Text PDFIndium tin oxide (ITO) nanocrystals 1-10 nm in size were grown via thermal treatment of a boroaluminosilicate parent glass. The nonlinear behavior of the obtained glass-ceramic was investigated with the Z-scan technique using 550 ps pulses of a 532 nm source at a 500 Hz repetition rate. The nonlinear response was rich, with the sample exhibiting third- and fifth-order nonlinearities as well as saturable absorption and two-photon absorption (TPA), depending on the locale probed.
View Article and Find Full Text PDFCoherent Ising machines (CIMs), leveraging the bistable physical properties of coherent light to emulate Ising spins, exhibit great potential as hardware accelerators for tackling complex combinatorial optimization problems. Recent advances have demonstrated that the performance of CIMs can be enhanced either by incorporating large random noise or higher-order nonlinearities, yet their combined effects on CIM performance remain mainly unexplored. In this work, we develop a numerical CIM model that utilizes a tunable fifth-order polynomial nonlinear dynamic function under large noise levels, which has the potential to be implemented in all-optical platforms.
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