We have modified the existing convolution method of the Monte Carlo simulation for finite photon beams with both translational and rotational invariance. The modified convolution method was applied to simulate the optical fluence distribution in tissue in dark-field confocal photoacoustic microscopy. We studied the influence of the size of the dark field and the illumination incident angle on t...

An experimental technique to characterize irradiation-induced swelling, or isotropic volume expansion, through a combined utilization of medium-to-high energy accelerators and interferometric surface profilometry, was established. The technique was successfully applied to a characterization of swelling behavior in beta-silicon carbide arising from the accumulation of point defects at relatively...

Time-resolved interferometry, surface light-scattering imaging, and optical microscopic imaging have been developed and applied to research on amorphous and multicrystalline films upon intense pulsed excitation. Nanosecond interferometry of neat polystyrene film gives interesting expansion dynamics followed by complete recovery. Femtosecond surface light-scattering imaging reveals the roughenin...

A principal factor in determining the biologic consequences of photodynamic therapy (PDT) is the light fluence rate. Preclinical and, more recently, clinical studies have focused on low-irradiance schemes, suggesting that prolonged light exposure, better known as CLIPT (continuous low-irradiance PDT), may improve tumor control while reducing morbidity. After a brief look at the origin of light ...

A Grazing Incidence Metal Mirror (GIMM) is a chief candidate for beam delivery for Inertial Fusion Energy (IFE). The goal for GIMM survival is greater than 3 10 8 laser pulses with 5 J/cm 2 laser fluence normal to the incident beam. Laserinduced damage to metal mirrors is primarily a thermomechanical process. Long-term exposure leads to microstructural evolution analogous to fatigue. We have pe...

We demonstrate the design, fabrication, characterization, and operation of high-density arrays of Au nanorod electron emitters, fabricated by high-resolution electron beam lithography, and excited by ultrafast femtosecond near-infrared radiation. Electron emission characteristic of multiphoton absorption has been observed at low laser fluence, as indicated by the power-law scaling of emission c...

For the assessment of radiation effects of clinical ion-beams, dosimetry has to be complemented by information on particle-energy distribution or related quantities. Fluorescence nuclear track detectors made from C,Mg-doped alumina single crystals allow for the quantification of ion track density and energy loss on a single-track basis. In this study, their feasibility and accuracy to quantify ...

This paper experimentally investigated the fabrication and optimization of micro-scale gratings formed by nanosecond laser etching. The mechanism of nanosecond laser processing and the geometric phase analysis (GPA) are discussed, and the factors influencing the fabrication process including laser energy, laser fluence, and ablation threshold of material, are experimentally studied. In order to...

The threshold laser fluence for the onset of surface melting is calculated for Ni films of different thicknesses and for a bulk Ni target using a combined atomistic-continuum computational model. The model combines the classical molecular dynamics (MD) method for simulation of non-equilibrium processes of lattice superheating and fast phase transformations with a continuum description of the la...

We measured 90% pump depletion in a singly resonant image-rotating nanosecond optical parametric oscillator that was pulse-injection seeded by a self-generated signal pulse. The oscillator was pumped by an 8 ns duration single-frequency 532 nm pulse from an injection-seeded Q-switched Nd:YAG laser and resonated an 803 nm signal. The pump and pulsed-seed beams had flat-topped spatial fluence pro...