The saturation properties of dye molecules that are rigidly held in a solid host are qualitatively different from those of molecules that are free to rotate. We have found that these unique saturation characteristics can be exploited to achieve nearly perfect vector phase conjugation for field strengths near the saturation intensity. We have studied these properties experimentally by using fluo...

The nonlinear optical properties of nanocrystalline-Si/SiO2 (nc-Si/SiO2) multilayers have been investigated through Z-scan technique by using a Ti-sapphire laser with 50-fs pulse duration at 800 nm as a pump laser. It is interesting to note that with increasing the annealing temperature to make the sample change from amorphous phase to nanocrystalline state, the nonlinear absorption turns the r...

Mode-locked vertical-cavity lasers have a large cross-sectional area and consequently a large saturation energy and large peak powers. We analyze excess optical bandwidth generation in these lasers and find that self-phase modulation due to optical pumping and gain saturation is the dominant factor in inducing laser pulse chirping. The large magnitude of the chirp makes intracavity prism-pair c...

this paper is a report on the synthesis of the fe3o4@ag core-shell with high saturation magnetization of magnetite nanoparticles as the core, by using polyol route and silver shell by chemical reduction. x-ray diffraction (xrd) and fourier transform infrared spectroscopy analyses confirmed that the particles so produced were monophase. the magnetic properties of the product were investigated by...

High speed, high efficiency, low noise and high saturation power are the characteristics desired for detectors in high bit-rate long-haul optical communication systems. We present modeling and initial experimental results on Traveling-wave Amplification Photodetectors (TAP detectors). These novel monolithic devices combine optical gain and absorption in a traveling-wave structure, providing hig...

In this paper, a fibre laser at 546 nm has been studied for a signal power of -30 dB. Er-doped ZBLAN fibre has been used by upconversion pumping of a 980 nm laser diode. Gain saturation effect has been investigated in detail. Laser performance has also been discussed. An efficiency of 35% has been calculated with a length of 5 mm fibre laser. Results show that Er-doped ZBLAN is a promising cand...

We study the combined effects of dynamic gain saturation and two-photon absorption on the amplification of short pulses in semiconductor optical amplifiers and show that two-photon absorption can saturate the amplifier gain and limit the output pulse energies even for amplifiers with large gain saturation energies. We discuss the upper limits for the pulse energies obtainable from semiconductor...

In this paper, a fibre laser at 546 nm has been studied for a signal power of -30 dB. Er-doped ZBLAN fibre has been used by upconversion pumping of a 980 nm laser diode. Gain saturation effect has been investigated in detail. Laser performance has also been discussed. An efficiency of 35% has been calculated with a length of 5 mm fibre laser. Results show that Er-doped ZBLAN is a promising cand...

We have used an adaptive optics confocal scanning laser ophthalmoscope to assess oxygen saturation in small retinal vessels. Images of the vessels with a diameter smaller than 50 μm are recorded at oxygen sensitive and isosbestic wavelengths (680 and 796 nm, respectively). The vessel optical densities (ODs) are determined by a computer algorithm. Then, OD ratios (ODRs), which are inversely prop...

Charge transport in semiconducting single-walled nanotubes (SWNTs) with Schottky-barrier contacts has been studied at high bias. We observe nearly symmetric ambipolar transport with electron and hole currents significantly exceeding 25 microA, the reported current limit in metallic SWNTs due to optical phonon emission. Four simple models for the field-dependent velocity (ballistic, current satu...