UNPs as HEDP simulators

A few interesting publications

Here are two excellent articles related to Zach Etienne's colloquium




Selected Publications

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Comment on "Generation of cold low divergent atomic beam of indium by laser ablation" [Rev. Sci. Instrum. 76, 113302 (2005)]
A. Denning, A. Booth, S. Lee, M. Amonson, and S. D. Bergeson
We present measurements of the velocity distribution of calcium atoms in an atomic beam generated using a dual-stage laser back-ablation apparatus. Distributions are measured using a velocity selective Doppler time-of-flight technique. They are Boltzmann-like with rms velocities corresponding to temperatures above the melting point for calcium. Contrary to a recent report in the literature, this method does not generate a subthermal atomic beam.
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Recombination fluorescence in ultracold neutral plasmas
We present the first measurements and simulations of recombination fluorescence from ultracold neutral calcium plasmas. This method probes three-body recombination at times less than 1 mu s, shorter than previously published time scales. For the lowest initial electron temperatures, the recombination rate scales with the density as n(0)(2.2), significantly slower than the predicted n(0)(3). Recombination fluorescence opens a new diagnostic window in ultracold plasmas. In most cases it probes deeply bound level populations that depend critically on electron energetics. However, a perturbation in the calcium 4snd Rydberg series allows our fluorescence measurements to probe the population in weakly bound levels that result just after recombination.
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Resonance Raman measurements of carotenoids using light-emitting diodes
N. Jay Eyring, Scott D. Bergeson, and Justin B. Peatross (et al.)
We report on the development of a compact commercial instrument for measuring carotenoids in skin tissue. The instrument uses two light-emitting diodes (LEDs) for dual-wavelength excitation and four photomultiplier tubes for multichannel detection. Bandpass filters are used to select the excitation detection wavelengths. The f/1.3 optical system has high optical throughput and single photon sensitivity, both of which are crucial in LED-based Raman measurements. We employ a signal processing technique that compensates for detector drift and error. The sensitivity and reproducibility of the LED Raman instrument compares favorably to laser-based Raman spectrometers. This compact, portable instrument is used for noninvasive measurement of carotenoid molecules in human skin with a repeatability better than 10%.

Theses, Captstones, and Dissertations

Figure from thesis
Frequency Locking Circuits (by Stephen Rupper)
We report the design and fabrication of a simple integral-gain feedback circuit. This circuit is used in our laboratory to control the frequency of single-frequency lasers. A short tutorial on feedback control is given. The \$80 control circuit will be used to replace more expensive commercial systems currently in use in our lab.
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Noise Characterization of an Injection-Locked Ti:sapphire Laser System (by Daniel Thrasher)
This thesis reports amplitude and frequency noise measurements of a Titanium:sapphire (Ti:sapphire) laser that is injection-locked with a low power diode laser. We use a heterodyne technique to frequency off-set lock a home built injection-locked Ti:sapphire laser with a low noise, commercial, injection-locked Ti:sapphire laser. Frequency noise measurements are made using the full-width-half-max of the two lasers’ beat note. Amplitude noise measurements are made using the root mean square (rms) of the output of a photo diode. Under optimal conditions the rms amplitude noise is 1.0% and the frequency noise is 300 kHz . The noise of our laser system depends on the feedback system characteristics. My contributions were the design and fabrication of a microwave interferometer, including its software and hardware, for the purpose of frequency off-set locking the two lasers. I also contributed to the data acquisition and analysis.
Figure from thesis
Ultracold Neutral Plasma Physics at Room Temperature (by Josh Wilson)
It has been shown that under certain conditions, the characteristics of ultracold neutral plasmas, can be reproduced in laser-produced plasmas at room temperature. We are attempting to see more fully how true this is, by trying to control the electron temperature in a laser-produced plasma. We expected that by decreasing the intensity of our laser when we ionize our gas we would see the expansion of our plasma slow down, and hence deduce that the electron temperature had been lowered. We had difficulty observing this result experimentally. We modeled the system and found that if we increase our laser intensity, we should be able to observe the phenomenon we had hypothesized. The experimental and modeling processes are here outlined, as well as thoughts on how to improve the experiment in the future.