Biomedical subjects

Jerome V Moloney

Publications and source records attributed to Jerome V Moloney.

6 recordsLinked to original sources

PubMed2006

Multichip vertical-external-cavity surface-emitting lasers: a coherent power scaling scheme.

We propose an efficient coherent power scaling scheme, the multichip vertical-external-cavity surface-emitting laser (VECSEL), in which the waste heat generated in the active region is distributed on multi-VECSEL chips such that the pump level at the thermal rollover is significantly increased. The advantages of this laser are discussed, and the development and demonstration of a two-chip VECSEL operating around 970 nm with over 19 W of output power is presented.

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PubMed2006

Closed-loop design of a semiconductor laser.

We provide what we believe is the first closed-loop prediction of a semiconductor laser performance using fully microscopic many-body models for the spontaneous emission, gain, and carrier recombination losses due to Auger processes without having to resort to phenomenological adjustable fit parameters.

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PubMed2006

Scintillation index for two Gaussian laser beams with different wavelengths in weak atmospheric turbulence.

We study the propagation of the two lowest-order Gaussian laser beams with different wavelengths in weak atmospheric turbulence. Using the Rytov approximation and assuming a slow detector, we calculate the longitudinal and radial components of the scintillation index for a typical free-space laser communication setup. We find the optimal configuration of the two laser beams with respect to the longitudinal scintillation index. We show that the value of the longitudinal scintillation for the optimal two-beam configuration is smaller by more than 50% compared with the value for a single lowest-order Gaussian beam with the same total power. Furthermore, the radial scintillation for the optimal two-beam system is smaller by 35%-40% compared with the radial scintillation in the single-beam case. Further insight into the reduction of intensity fluctuations is gained by analyzing the self- and cross-intensity contributions to the scintillation index.

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PubMed2005

Intersection of nonidentical optical waveguides based on photonic crystals.

An intersection based on photonic crystal coupled resonator optical waveguides is proposed and analyzed. The two waveguides are designed to have different transmission bands without overlap, which enables light in the two corresponding bands to propagate through the intersection with no cross talk and with excellent transmission. The MIT Photonic-Bands code is used to calculate the band structures of photonic crystal waveguides. The finite-difference time-domain method is used to simulate the relevant structures.

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PubMed2005

Kink shape solutions of the Maxwell-Lorentz system.

In the limit of high amplitude oscillating electromagnetic fields, a sequence of kink antikink shaped optical waves has been found in the Maxwell's equations coupled to a single Lorentz oscillator and with Kerr nonlinearity. The individual kinks and antikinks result from a traveling wave assumption and their stability has been assessed by numerical simulations. For typical physical parameter values the kink width is of the order of tens of femtoseconds.

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PubMed2004

Self-healing femtosecond light filaments.

A recent experiment [Appl. Phys. Lett. 83, 213 (2003)] indicated that filaments created in femtosecond high-power pulses propagating in air are surprisingly robust when interacting with microscopic water droplets. We present numerical modeling of the dynamics of the filament-droplet interaction. Our simulation results provide further insight into the interplay between the filament's core and the wide transverse pedestal of the pulse. It is shown that the robustness of the filament comes from the transverse low-intensity pedestal that controls the formation of the central hot spot. Implications for penetration of wide, high-power beams through obscurants are discussed.

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