Fixed Pump Power Research Articles

Timing Jitter and Pulse Width Reduction in a Hybrid Q-Switched Cr,Nd:YAG Laser

We present a detailed study of a combined actively and passivelyQ-switched (CAPQ) laser with an acousto-optic modulator (AOM) and acodoped Cr4+, Nd3+:YAG crystal. The hybrid Q-switchapproach is used to produce a short laser pulse with stable and tunablerepetition rates. The timing jitter, average pulse width, and averagepulse amplitude vary periodically with the AOM modulation frequencyunder a fixed pump power. The repetition rate of the CAPQ laser can beturned approximately from 4 kHz to 16 kHz with the jitter less than400 ns.

InAs/InP quantum dots in SiO2/Ta2O5-based microcavities

Planar InAs/InP quantum-dot microcavities using multilayer SiO2/Ta2O5 Bragg reflectors have been studied in emission. For an eight-pair mirror design, the stop band extends from 700 to 900 meV and the cavity linewidth is ∼500 μeV for emission at 850 meV. Measurements as a function of incident power show quantum-dot saturation behavior, with the emission intensity going to the wetting layer outside the cavity stop band. Saturation behavior at fixed pump power is also observed as a function of decreasing temperature. Dispersion measurements as a function of emission angle show polarization splitting in reasonable agreement with theory.

Optical Properties of InAs/InP Planar Quantum Dot Microcavities

ABSTRACTPlanar InAs/InP quantum dot microcavities using multi-layer SiO2/Ta2O5 Bragg reflectors have been studied in emission. The spectra exhibit collection optics-limited cavity linewidths of ∼1meV with the occasional ∼200μeV single-dot emission. Measurements as a function of incident power show quantum dot saturation behavior, with transfer of oscillator strength to the wetting layer outside the cavity stop band. Saturation behavior at fixed pump power is also observed as a function of decreasing temperature. Dispersion measurements as a function of emission angle show polarization splitting in qualitative agreement with theory.

Regular, period-doubling, quasi-periodic, and chaotic behavior in a self-mode-locked Ti:sapphire laser

Regular, period-doubling, quasi-periodic and chaotic behavior in a self-mode-locked Ti:sapphire laser was observed under fixed pump power during alignment of the laser cavity .

Cavity optimization for minimum pulsewidth of gain-switched semiconductor lasers

The optimum photon lifetime for the minimum pulsewidth of a gain-switched laser is investigated both analytically and numerically. For a fixed pump power, the shortest pulse can be produced when the laser cavity is optimized to give an optical pulsewidth that is /spl sim/2.5 times the photon lifetime. This is in good agreement with experimental results.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Tuning characteristics of a high pressure CO2 laser pumped CH3F Raman laser

We described a CH3F Raman laser pumped by a two stage 20 atmospheres CO2 laser. The emission spectrum of the CH3F laser at 11 Torr extends from 23 cm−1 to 45 cm−1 when the CO2 laser is scanned over the 9R emission branch at a fixed pump power of 180 mJ. The emission spectrum shows a strong structure with large parts where the FIR energy decreases to zero. This fact makes the use of such a laser for spectroscopic scanning experiments in the FIR difficult. The laser is, however, very suited for working at fixed but adjustable FIR frequencies. The pulse energy in the maxima of the emission characteristics at a pump energy of 180 mJ exceeds 300 μJ, which corresponds a photon conversion coefficient of more than 6%.

Traveling Wave Analysis of a Class of Parametric Amplifiers Based upon the Hill Equation

A general traveling wave analysis is given for electron beam parametric amplifiers in which the electron dynamical equation in the pump is a Hill's differential equation. Formulas are given for the complex wave number of beam waves, and clear conditions for growing wave solutions are presented. The special case of a sinusoidal pump field variation is treated, and the optimum pumping condition is found to result when the pump frequency is twice the beam natural frequency. It is shown that growing wave solutions exist at pump frequencies which are rational fractions of the beam natural frequency, but that the growth constants for these pumping conditions (at fixed pump power) are orders of magnitude less than under the optimum condition.