Title of Thesis: CHARACTERIZATION OF TWO-PHOTON ABSORPTION DETECTORS FOR APPLICATIONS IN HIGH-SPEED OPTICAL SYSTEMS Degree candidate: Reza Salem Degree and year: Master of Science, 2003 Thesis directed by: Professor Thomas E. Murphy Department of Electrical and Computer Engineering This thesis investigates the process of two-photon absorption in optical detectors. We begin by describing some co...

Ultrafast laser processing applications need fast approaches to assess the nonlinear propagation of the laser beam in order to predict the optimal range of processing parameters in a wide variety of cases. We develop here a method based on the simple monitoring of the nonlinear beam shaping against numerical prediction. The numerical code solves the nonlinear Schrödinger equation with nonlinear...

Polyurethane closed cell (PUCC)/SiO2 nanocomposites have been prepared by using in situ polymerization approach. The third-order optical nonlinearities of PUCC/SiO2 nanocomposites, dissolved in DMF are characterized by Z-scan technique at the measurement wavelength of 532 nm. The nonlinear refractive (NLR) indices and nonlinear absorption (NLA) coefficients of samples were calculated from close...

In this study, Highly Oriented Pyrolytic Graphite was ablated in various polar and nonpolar solvents by Q-switched neodymium: yttrium-aluminum-garnet laser (wavelength=1064 nm, frequency=2 kHz, pulse duration=240 ns). Then, the products were examined using Scanning Electron Microscopy and UV-Vis spectroscopy. The images showed that different carbon structures such as cauliflower-like structures...

We report a novel photoacoustic Z-scan (PAZ-scan) technique that combines the advantages offered by the conventional Z-scan method and the sensitivity of the photoacoustic detection. The sample is scanned through the focused laser beam and the generated photoacoustic signal is recorded using a 10 MHz focused ultrasound transducer. Since the signal strength is directly proportional to the optica...

This paper aims to study the nonlinear absorption characteristics of palladium nanoparticles (PdNPs) at off-resonant wavelengths. For this purpose, multi-wavelength (500–650 nm) nanosecond Z-scan technique was used. The experimental results indicate that saturated (SA) and transition from SA reverse (RSA) can occur, depends on excitation wavelength energy. When is constant, with increase energy...

We study theoretically absorption properties of MoS2 quantum dots placed in an ultrashort and strong optical pulse with the duration a few femtoseconds amplitude up to 1.5 V/Å. While monolayer has bandgap ≈1.8eV, have in-gap edge states, which open additional channels. The absorbance system strongly depends on pulse. At small amplitude, less than 0.5 V/Å, varies by more 20% frequency shows satu...