Pulsed Xenon Research Articles

Total reflection resonator with hole coupling

Total internal reflecting surfaces have been proposed as regenerative structures for solid-state lasers; the laser energy is extracted from the resonator through frustrated total re­ flection by a coupling prism. Instead of using frustrated total reflection to extract the energy, we found the energy can be extracted through a hole on the tip of the total reflecting surface. In this experiment, we polished the two ends of a Nd:Yag laser rod into 90° cones with one cone tip polished into a small flat surface (1 mm in diam, with no intention of optimizing the output coupling) as shown in Fig. 1. The 90° cones from the total internal reflecting surfaces and the small flat surface are used as an energy output port. Intuitively, this structure is more or less similar to the hole coupling used in CO2 lasers. This Nd:Yag laser rod, 69 mm in length and 5 mm in diam, with 1.2% Nd + 3 concentration, is then put into a gold-coated circular cavity and pumped by a pulsed xenon flashlamp. The typical discharge condition was a capacity of 50 μF and 600 V. The output energy detected by a P-I-N photodiode

The ethylperoxy radical spectrum and rate constant for mutual interaction measured by flash photolysis and kinetic spectroscopy

AbstractIntrinsic spectral and kinetic parameters have been measured for the ethylperoxy radical, which was formed in the gas phase by the flash photolysis of azoethane in the presence of an adequate excess of oxygen. Absolute values of the extinction coefficient ϵ(λ) were derived from complementary measurements of the yield of nitrogen and the absorbance of an equivalent concentration of ethylperoxy radicals. The absorption spectrum is broad, structureless and comparatively weak; ϵ(236) = 1.02 × 103 liter mole−1 cm−1 at the maximum, and the oscillator strength is 3.4 × 10−2. This spectrum resembles the spectrum of the methylperoxy radical closely in form, but it is less intense; the ratio of the values of oscillator strength is 0.5. The bimolecular reactions of mutual interaction of ethylperoxy radicals are not exclusively terminating, and ethoxy and hydroperoxy radicals are formed in kinetically significant quantities. A computer program was designed to simulate the rise and fall of the concentration of each radical species, and to perform the related kinetic analysis. This program predicted that a second‐order plot of the decline of the absorbance of the ethylperoxy radical during the dark period would not show a significant departure from linearity, a conclusion which was confirmed by experiment. Accordingly, the gradient of each such plot yielded a value of k'/ϵ(λ), where k' is the apparent value of the rate constant for the collective reactions of mutual interaction. This rate constant was evaluated from the product of corresponding values of k'/ϵ(λ) and ϵ(λ); individual values are independent of the wavelength of measurement, and the mean value is k' = (6.6 ± 0.5) × 107 liter mole−1 sec−1. Further kinetic analysis yielded the corresponding absolute value: k = (6.0 ± 0.6) × 107 liter mole−1 sec−1. This value fits the pattern of a relationship between rate constant and structure shown by the methylperoxy, isopropylperoxy, and tert‐butylperoxy radicals. Adequate sensitivity for the characterization of the spectrum of the ethylperoxy radical was achieved by the use of a pulsed xenon arc as the monitoring light source in conjunction with a dual beam detection system with twin cells and balanced photomultipliers, and the apparatus is described in detail.

A xenon ion pumped open dye stream laser

A pulsed xenon ion laser with an output power of 1 kW over the blue-green lines was used to pump an open dye stream laser. An efficiency of the order of 40 percent was determined in broad-band mode operation. The bandwidth in this case was 48 nm (from 582 to 630 nm).

A xenon ion pumped blue dye laser

A pulsed xenon ion laser with an output power of 5 kW at 364.5 nm has been used as a pump source for several blue dyes. Broad-band conversion efficiencies exceed 20 percent. The use of a birefringent filter provides tunable output in the blue region of the spectrum with a bandwidth of 0.08 nm and a pulsewidth of 120 ns.

Fluorescence ambient NO_2 monitor with flashlamp pumping

A pulsed xenon flashlamp unit was developed to provide a sensitive, economical, and compact device for determination of ambient NO(2) concentrations. The basic principles of operation are similar to a laser fluorescence monitor previously developed at the Aerospace Corporation that detects the atmospheric NO(2) by the fluorescence resulting from absorption of laser radiation. The prototype flashlamp unit has a sensitivity of 5 ppb for a 1.3-min integration time, a linear response, and provides a direct digital readout in real time. Results obtained in monitoring ambient NO(2) levels in the vicinity of the Aerospace Corporation are presented.

Comparison of figures of merit for fluorimetric analysis of rhodamine complexes of gallium and indium by excitation with pulsed laser and by xenon arc sources

Optimum conditions have been established for formation and extraction of indium-Rhodamine complexes, and limits of detection found for fluorimetric determination of gallium and indium by means of Rhodamine dyes, using the excitation with pulsed laser and xenon arc sources.

Superheating instability in a pulsed xenon discharge

It is shown that previously obtained conditions for superheating instability substantially vary if we take into account secondary xenon ionization. Instability completely vanishes if the density of heavy particles in the discharge is kept constant and whenever a discontinuous time variation of temperature T in a restricted region between 15 · 103 ° K and 20 · 103 ° K is possible for a constant effective pressure. The development of instability is studied numerically by a ranging method. Stationary temperature distributions possessing a high contrast as a local temperature passes through a given range of instability with constant pressure are presented.

Investigation of pulsed xenon lamps with additions of molecular gases

Investigation of pulsed xenon lamps with additions of molecular gases

A high-power pulsed xenon ion laser as a pump source for a tunable dye laser

An inexpensive pulsed xenon ion laser with peak power outputs up to 4 kW has been constructed and used as a pump source for a tunable rhodamine 6G dye laser with a 0.25-Å bandpass in the yellow-red range of the spectrum. The dye laser is tunable from 5465 to 6300 Å. Over 50 W are obtained at the peak of the tuning range.

Some observations on multiply ionized xenon laser lines

The intensity profile of the laser lines in pulsed xenon discharges is related to the Xe(IV) emission from the plasma pinch. The period of the observed intensity modulation of the xenon-laser pulse corresponds to the time for double traversal of the cavity. Evidence is reported for local saturation of two Ar(II) laser lines in pulsed argon discharges.

Influence of the plane of polarization on the photo-emission of electrons

The influence of the plane of polarization on electron emission into solution has been investigated using plane polarized light obtained by frequency doubling the polarized output of a ruby laser and also polarized light derived from a pulsed xenon arc. Results obtained with mercury pool and amalgamated silver electrodes reveal little direct dependence on the direction of the electric vector though there is an indirect dependence connected with the influence of the vector direction on absorbance. Electron emission results from the homogeneous formation in the mercury phase of “hot” electrons some of which after inelastic and elastic collisions have sufficient energy to evaporate into the solution. The theoretical consequences of this mechanism for electron emission into solution are briefly discussed together with the possible effect of solvent orientation on emission.

Influence of the plane of polarization on the photoemission of electrons

The influence of the plane of polarization on electron emission into solution has been investigated using plane polarized light obtained by frequency doubling the polarized output of a ruby laser and also polarized light derived from a pulsed xenon arc. Results obtained with mercury pool and amalgamated silver electrodes reveal little direct dependence on the direction of the electric vector though there is an indirect dependence connected with the influence of the vector direction on absorbance. Electron emission results from the homogeneous formation in the mercury phase of “hot” electrons some of which after inelastic and elastic collisions have sufficient energy to evaporate into the solution. The theoretical consequences of this mechanism for electron emission into solution are briefly discussed together with the possible effect of solvent orientation on emission.

Construction of a high power xenon ion laser

Construction of a pulsed xenon ion laser, which has a combined peak power on all visible lines of over 80 kW is described. Design of the laser and the pulsing circuit is detailed, and the light pulse shape, peak power and electrical effieciency of the laser are discussed.

Determination of the refractive index of strontium vapors by means of a pulsed xenon laser

Determination of the refractive index of strontium vapors by means of a pulsed xenon laser

A high-power pulsed xenon ion laser

Output and threshold characteristics of small-bore pulsed xenon ion lasers are presented in detail as a function of current and gas pressure for ranges of these parameters that are consistent with high optical power output in the green-blue spectral region. It has been found that six wavelengths characteristic of xenon exhibit peak output powers greater than 100 watts, from a 5-foot laser tube over a limited (8-24 mtorr) range of xenon tube pressure. Laser action has also been obtained at high peak powers for longer current pulse ( 5-50 \mu s) operation of the tube. In addition, observation of three new laser wavelengths 5340, 5501, and 5590 A is reported. These lines are only observed at very low tube pressures and very high peak currents.

Photocurrents at irradiated mercury electrodes in solutions of nickel ions

The influence of concentration and potential on photocurrents produced at mercury electrodes in solutions of nickel ions have been investigated using a pulsed xenon lamp. It is concluded that the mechanism involves scavenging of hydrated electrons by the nickel ions followed by an oxidative regeneration, rather than the reduction of excited nickel ions.

INTENSITY LIMITATION AND ENERGY SPREADING IN AN OPTICAL FIELD UNDER TRANSIENT THERMAL DEFOCUSING CONDITIONS

An experimental investigation was made of two new effects of transient thermal defocusing. These effects were the limitation of the peak intensity of the pulses and spreading of the energy in the optical field. In both effects an important quantity was the energy of a nonlinear precursor Wpr. The intensity limitation was observed when the energy of the leading edge was greater than Wpr. The spreading occurred when the energy of the whole pulse was greater than Wpr. The experiments were carried out for pulsed xenon radiation in an alcoholfilled cuvette. The calculation equations for these two effects were derived.

Nd:YALO oscillation at 0.930 µm at 300 K

Oscillation at 0.930 μm was obtained by end pumping a c -axis Nd:YALO rod at 300 K with the output of a pulsed xenon ion laser.

A high performance graphic arts lamp

A very high optical performance can be achieved by enclosing a metal halide lamp, suitably doped for the printing and reprographics industry, in a sealed beam reflector and refractor enclosure. The period of exposure needed under this very actinic light source is considerably shorter than that required by pulsed xenon, mercury vapour or the carbon arc and its enclosed optics ensure an excellent u.v. maintenance throughout a long life. Designed to be used on a 240 V a.c. supply the lamp consumes 400 watts and operates with a choke ballast and starter unit.

Effects of an axial magnetic field on the output power of a pulsed xenon laser

Data indicating the effects of an axial magnetic field on the output power of a pulsed xenon laser are presented. The output power increased significantly with increasing axial magnetic field only for low output power levels.