Xe Flash Lamp Research Articles

Comparison of N2, Xe, Kr, and ArF excimer flashlamps with respect to their suitability for pumping TlI

The far UV spectra of a flashlamp with a rise time of 30 ns filled with either N2, Xe, Kr, or Ar, F2, He mixtures at 1 bar have been recorded. Emission of these flashlamps are compared in a band ranging from 190 to 220 nm. It is shown that the N2 and ArF flashlamps produce an nearly identical output and are best suited for TlI photodissociation. The light energy in this band with respect to the total emission from 190 nm to 4.5 μm amounts to 7% for N2 and 15%–25% for ArF.

On the efficiency of long Xe flashlamps

On the efficiency of long Xe flashlamps

A high efficiency HF(H2/F2) chemical laser initiated with a surface-spark ultraviolet flash

As a novel alternative to the conventional Xe flash lamps, a surface-spark-discharge ultraviolet (UV) flash with a poly-tetra-fluoroethylene (Teflon) resin was utilized to an initiation of a H2/F2 chemical laser. Because we employed a high-voltage and low-inductance power supply to drive a surface-spark flash, a stabilized surface discharge in a high pressure (≃1 atm) laser gas and high efficiency power input to an UV flash have been realized. We have obtained a maximum HF laser output energy of 8.5 J/pulse (14.6 J/ ∂) at an electrical efficiency of 9.7%. A surface-spark light source is experimentally found to be able to uniformly initiate a large-volume laser gas mixture.

Time resolved spectroscopy of large bore Xe flashlamps for use in large aperture amplifiers

Time resolved spectroscopy was performed on 13-mm xenon filled flashlamps. The use of a well-characterized system allowed the acquisition of absolute radiometric data. The data were compared to the predictions of a phenomenological flashlamp model and differences noted. Specifically the arc for equal currents is not the same for dI/dt > 0 and dI/dt < 0, the continuum is a stronger function of current density than the model indicated, and different lines, linewidths, and line intensities were found.

Synchronized flash light source optical detection for electric field-jump relaxation experiments

An electric field-jump apparatus is constructed, with a synchronized Xe flash lamp for photometric monitoring of chemical relaxations. The instrument is especially useful for the investigation of linear macromolecules, where the analyzing light beam must be linearly polarized. A video amplifier is used in conjunction with the photomultiplier, providing for fast rise time and low noise of the detection system.

Laser action of pulse-pumped Nd3+ : Gd3Ga5O12 at 1.054 μm

Laser action at 1.054 μm was obtained in a neodymium-doped Gd3Ga5O12 crystal pumped by a Xe flashlamp. The output power of laser oscillation at 1.054 μm have been measured comparable to that of Nd3+ : YAG laser at 1.052 μm.

Quenching of N2(A 3Σ+u) by I2

Production and decay of N2(A 3Σ+u) (v=0, 1, 2) states were monitored photoelectrically from the sensitized fluorescence of NO γ bands. These states were produced by collisional transfer from excited Xe (1S4) which in turn was produced by radiative energy transfer via resonance radiation (147 nm) from a closely coupled Xe flash lamp. The rate coefficient for the deactivation of N2(A 3Σ+u) by I2 was measured as kI2= 6.9±1.9×10−12 cm3/sec. The deactivation by NO itself was measured as kNO=4.5±0.5×10−11 cm3/sec.

Flash-lamp-excited NdP5O14 laser

A simple miniature room-temperature pulsed NdP5O14 laser excited by a small Xe flash lamp has been made, with threshold energies of a few hundred millijoules. Output energies of 1.5 mJ have been obtained with less than 1 J input, and an order-of-magnitude improvement is expected.

Reaction probabilities of hot hydrogen atoms with CO2 and N2O

Hot H atoms (H*) from the photodissociation of HI in the gas phase react with CO2 according to H*+ CO2→ OH + CO and with N2O according to H*+ N2O → NH + NO. Exciting light from a Xe flash lamp in a silica envelope led to H* with an average initial energy of 57 kcal/mol. Experimental yields of NH+4, the ultimate product following (2), and of CO were analysed kinetically and the following relative reaction probabilities deduced: k1a/(k1a+k1c)= 0.0219 and k2a/(k2a+k2c)= 0.0104 where subscript “a” refers to reaction and subscript “c” refers to collisional cooling without reaction. Effects of added He and Ar allowed estimation of the relative numbers of collisions needed to cool H* to energy just below that for reaction; NCO2/NHe and NCO2/NAr are 1.8 and 0.49, respectively, indicating that, if the rare gases are acting as hard spheres, collisions of H* with CO2 are inelastic. Reaction and cooling parameters in the theory of Wolfgang and Estrup are also evaluated from the data.

Comparison of Kr and Xe flashlamps for Nd:YAG lasers

Linear krypton and xenon flashlamps (6-mm bore, 3-inch arc) having various fill pressures between 450 torr and 4 atm have been operated in a single elliptical gold-plated pump cavity to excite a Nd:YAG laser rod (0.25-inch diameter, 3 inches long). Here we describe laser operation as a function of lamp fill, for electrical input energies ranging from 2 to 40 joules (120-μs pulse duration) and for pulse repetition rates from single shot to 20 Hz. We have found that Kr lamps are generally superior to Xe lamps for pumping Nd: YAG except at high current densities. Specifically, for this system (the parameters of which are suitable for commercial and military applications), the optimum Kr fill pressure is approximately 700 torr, while the optimum Xe fill pressure is roughly 1000 torr. The threshold with the 700-tort Kr lamp is 58 percent of that with the 1000-torr Xe lamp; the crossover energy (for equal absolute efficiencies) is 40-joule input, which in our system corresponds to about 375-mJ output.

Angular Dependence of Two Photon Absorption in Thallous Chloride

A measurement on the dependence of two photon absorption coefficient on the polarization angle of light in thallous chloride was performed. Two polarized light beams, one from Nd-glass laser and another from Xe-flash lamp, were made incident on the sample from the antiparallel directions, and the directions of both polarizations were rotated. The angular dependence was found to belong mostly to A 1 g representation in octahedral group from the band edge (∼3.56 eV) to as high as 4.2 eV. But the angular dependence was found to change at higher energy, and N g component seemed to mix with A 1 g . Two photon absorption spectra at liquid nitrogen temperature confirmed the assumption that the two photon transition spectrum was of the second class. A discussion about the method of analysis for this type of transition is presented.