Femtosecond optical Kerr effect in normal and grades of cancerous breast tissues as a new optical biopsy method.

This study reports on the first use of the optical Kerr effect (OKE) in breast cancer tissue. This proposed optical biopsy method utilizes a Femtosecond Optical Kerr Gate to detect changes in dielectric relaxation and conductivity created by a cancerous infection. Here, the temporal behavior of the OKE is tracked in normal and cancerous samples of human and mouse breast.

Femtosecond Optical Kerr Gate in tissues.

The Optical Kerr Effect is investigated for the first time in biological tissues. This nonlinear effect was explored in both human brain and avian breast tissues using a time-resolved femtosecond pump-probe Optical Kerr Gate that looks for phase changes that arise in the probe from the pump induced Kerr refractive index change. The tissue samples produced a unique ultrafast (700-800 fs) doubled peaked temporal signal, which is indicative of interplay between the different ultrafast mechanisms (electronic plasma and molecular) that make up the Kerr index.

Femtosecond Optical Kerr Gates in Cancerous Breast Tissue for a New Optical Biopsy Method.

The Optical Kerr Effect was demonstrated for the first time as a new optical biopsy method to detect normal and grades of cancer of human breast tissues. The technique works by temporally tracking the various electronic and molecular processes that give rise to the nonlinear index of refraction (n). The rate at which these processes populate and dissipate varies depending on the internal properties of the sample.

Technical note: Monte Carlo study of the mechanism of proton-boron fusion therapy.

Purpose: Proton beam therapy has been found to have enhanced biological effectiveness in targets that contain the boron isotope B, with the alpha particles resulting from the p + B → 3α reaction being hypothesized as the mechanism; in this study, we aimed to elucidate the causes of the enhanced biological effectiveness of proton-boron fusion therapy by performing a detailed Monte Carlo study of the p + B → 3α reaction in a phantom geometry.

Methods: We utilized the Geant4 toolkit to create Monte Carlo particle physics simulations. These simulations consisted of a proton beam with a range 30 mm, creating a Spread-Out Bragg Peak with a modulation width of 10 mm, directed into a water phantom containing a region of boron material.

Femtosecond anti-Stokes conical emission in BK-7 glass and O and E-wave calcite.

The angle of anti-Stokes conical emission (CE) is experimentally measured in the frequency shift span of 2000 to 9000. The experiment was performed using a 800 nm 50 fs laser pump in samples of BK-7 glass and calcite in both the O and E-wave configurations. The experimental results of angular emission are then compared to three competing models: the Alfano-Shapiro four wave mixing (FWM) model from 1970, the Luther FWM model from 1994, and the Faccio X-wave model from 2004.

Steady-state stimulated Raman generation and filamentation using complex vector vortex beams.

Stimulated Raman scattering and laser filamentation produced using nanosecond pulsed complex vector vortex beams (CVVB) are investigated in a 20 cm long methanol cell. The CVVB is generated using -plates and is tested at orbital angular momentum () values of 1, 2, 3, and 4 and circular, radial, and azimuthal polarizations. The results illustrate that the stability and intensity of the generated stimulated Raman has dependence on input polarization and value.

Explanation of the competition between O- and E-wave induced stimulated Raman and supercontinuum in calcite under ultrafast laser excitation.

Key optical properties of calcite were measured to unravel the difference between stimulated Raman scattering (SRS) and self-phase modulation (SPM) for the supercontinuum (SC) for ordinary (O) wave and extraordinary (E) wave. These properties are group velocity dispersion, walk-off, spontaneous Raman spectra and cross section, optical 1086 phonon linewidth, nonlinear susceptibility (), steady-state and transient SRS, and SC caused from SPM. These are investigated for O-waves and E-waves from a 2.

Inhibition of multi-filamentation of high-power laser beams.

We experimentally demonstrate the control and complete elimination of multi-filamentation in condensed matter by varying the focusing geometry. In particular, increasing the input beam power enables the extension of the filament length without generating multi-filaments up to 1400 times the critical power in fused silica at an 800 nm wavelength. Furthermore, the generated single filament exhibits spatial solitary wave behavior.