Introduction: Residual oxygen-free radicals of bleaching agents before composite restorations can increase microleakage in enamel and dentin margins, and also various bleaching techniques are being developed using light sources. The present study was conducted to compare the effect of diode laser bleaching and LED activated bleaching on the microleakage of composite restorations. Materials & M...

We theoretically investigate the possibility of realizing a nonlinear all-optical diode by using the unique features of quasiperiodic 1D photonic crystals. The interplay between the intrinsic spatial asymmetry in odd-order Thue-Morse lattices and Kerr nonlinearity, combined with the unconventional field localization properties of this class of quasiperiodic sequences, gives rise to sharp resona...

The characteristics of the GaN/InGaN multiquantum-well light-emitting diode ~LED! have been examined from the view point of uniform current spreading. By means of simple modeling, it was found that the current density and the length of the lateral current path through the transparent layer represent dominant parameters in determining uniform current spreading. In this regard, we studied the eff...

Flattening filter-free (FFF) beams are becoming the preferred beam type for stereotactic radiosurgery (SRS) and stereotactic ablative radiation therapy (SABR), as they enable an increase in dose rate and a decrease in treatment time. This work assesses the effects of the flattening filter on small field output factors for 6 MV beams generated by both Elekta and Varian linear accelerators, and d...

We present a method to include the effects of light excitation on two different models of resonant-tunneling-diode-based devices. Our approach takes into account both photoconductive and charge accumulation effects responsible for shifting the static I – V curve when the structure is under light excitation. Computational simulations led to good agreement between the model and experimental resul...

The effect of a slight misalignment in the magnetic field on a magnetically insulated diode is investigated. It is found that a slight tilt in the magnetic field, with a minute component along the dc electric field, completely destabilizes the cycloidal electron flow in the crossed-field gap. The final state consists of the classical Brillouin flow superimposed by a turbulent background, togeth...

We report novel photovoltaic (PV) switching based on the low exciton-binding energy property of an organic heptazole (C26H16N2) thin film after fabrication of an heptazole-based Schottky diode. The Schottky diode cell displayed an instantaneous voltage of 0.3 V as an open circuit voltage (VOC) owing to the work function difference between the Schottky and ohmic electrode under deep blue illumin...

Gate leakage currents in AlGaN/GaN heterostructure field-effect transistor ~HFET! structures with conventional and polarization-enhanced barriers have been studied. Comparisons of extensive gate leakage current measurements with two-dimensional simulations show that vertical tunneling is the dominant mechanism for gate leakage current in the standard-barrier HFET and that the enhanced-barrier s...

We measure and simulate numerically the Hanle effect and non-zero field level crossing signals in 85Rb and 87Rb atoms in a magnetic field at room temperature. Diode laser radiation from 4 mW cm−2 to 3.3 W cm−2 tuned to the D2 absorption line of each isotope excites atoms into all the excited-state hyperfine levels simultaneously inside the unresolved Doppler profile. Polarization fluorescence d...