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C Cojocaru

Publications and source records attributed to C Cojocaru.

11 recordsLinked to original sources

Subdiffractive light pulses in photonic crystals.

We investigate propagation of light pulses in photonic crystals in the vicinity of the zero diffraction point. We show that Gaussian pulses due to nonzero width of their temporal spectrum spread weakly in space and time during the propagation. We also find the family of nonspreading pulses, propagating invariantly in the vicinity of the zero diffraction point of photonic crystals.

Journal Article↗

Nonadiabatic dynamics of the electromagnetic field and charge carriers in high-Q photonic crystal resonators.

We address, both experimentally and theoretically, phase and amplitude dynamics of the electromagnetic field in a two-dimensional photonic crystal when femtosecond pulses are injected. We demonstrate that the usual adiabatic approximation underlying the dynamics of field and carriers in a semiconductor resonator is no longer valid, since in general the photon lifetime cannot be neglected with respect to the carrier recombination lifetime. Parameter regions where adiabaticity is broken are shown, and the ubiquity of the observed dynamical scenario in the new generation of active photonic microresonators is predicted.

Journal Article↗

Tuning a two-dimensional photonic crystal resonance via optical carrier injection.

We report on wide wavelength tuning through optical injection of carriers of a photonic resonance observed in reflectivity at 1543 nm in an InP-based two-dimensional photonic crystal slab. An 8-nm blueshift, which represents 20 times the resonance linewidth, is observed when a 4-kW/cm2 intense optical pump is incident on the sample. An analytical model that we developed, based on a coupled-mode nonlinear approach, allows us to describe this phenomenon in detail.

Journal Article↗

[Charleux's method of basal iridectomy].

Retrograde transcorneal iridectomy suggested by Charleux and Etienne was used in 27 eyes (20 patients) suffering from glaucoma with closed angle (in 12 eyes with acute attack and in 15 congeneric eyes) (prophylactic). The post- or intrasurgical complications were absent. The operation was simple and had good results. The hospitalization period was of 2-3 days.

Aged↗

Ergonovine test in coronary disease.

The authors present the role of the Ergonovine test in establishing the diagnosis of the angina produced by coronary spasm. ECG alterations induced by Ergonovine, like transparietal ischemia (monophasic wave) or subendocardic ischemia, not only make possible a correct diagnosis, but they also underline the mechanism of angina and the therapeutical measures. Severe arrhythmias and the danger of sudden death are the two elements illustrating the importance of this coronary spastic mechanism. Nitroglycerine, isosorbidinitrate and calcium antagonists are the drugs of election for the prevention and also for the treatment of coronary spasm.

Adult↗