The Optically Pumped Difluoromethane Far-Infrared Laser

Danielewicz, E.

doi:10.1007/978-1-4613-2689-2_12

Cited by 7 publications

(2 citation statements)

References 16 publications

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“…These low values were motivated by fission fragment spectra (Hofmann and Nix 1983). However, recently hot fission experiments recently led to much higher extracted viscosity coefficients (Paul Private communication) in accordance with the estimates of kinetic theories (Bodmer 1978, Danielewicz 1984. Recent hydrodynamical calculations (Schmidt 1989) show that only such high viscosity coefficients can explain the flow and bounce-off data.…”

Section: Siopping and Thermalizationsupporting

confidence: 58%

Physics of high-energy heavy-ion collisions

1994

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This is a review of the present status of heavy-ion collisions at intermediate energies. The main goal of heavy-ion physics in this energy regime is to shed some light on the nuclear equation of state (EO?.), hence we present the basic concept of the EOS in nuclear matter as well as of nuclear shock waves which provide the key mechanism for the compression of nuclear matter.The main part of this article is devoted to the models currently used for describing heavy-ion reactions theoretically and to the observables useful for extracting information about the EOS from experiments. A detailed discussion of the flow effects with a broad comparison with the available data is presented.The many-body aspects of such reactions are investigated via the multifragmentation break up of excited nuclear systems and a comparison of model calculations with the most recent multifragmentation experiments is presented.

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Section: Siopping and Thermalizationsupporting

confidence: 58%

Physics of high-energy heavy-ion collisions

1994

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“…Their wavelengths range from approximately 95.6 to 1714.1 μm. [13][14][15] Nearly 75% of these laser emissions have had their frequencies measured while several have been spectroscopically assigned [16][17][18] .…”

Section: Introductionmentioning

confidence: 99%

Characterizing Far-infrared Laser Emissions and the Measurement of Their Frequencies

Jackson

Zink

2015

JoVE

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The generation and subsequent measurement of far-infrared radiation has found numerous applications in high-resolution spectroscopy, radio astronomy, and Terahertz imaging. For about 45 years, the generation of coherent, far-infrared radiation has been accomplished using the optically pumped molecular laser. Once far-infrared laser radiation is detected, the frequencies of these laser emissions are measured using a three-laser heterodyne technique. With this technique, the unknown frequency from the optically pumped molecular laser is mixed with the difference frequency between two stabilized, infrared reference frequencies. These reference frequencies are generated by independent carbon dioxide lasers, each stabilized using the fluorescence signal from an external, low pressure reference cell. The resulting beat between the known and unknown laser frequencies is monitored by a metal-insulator-metal point contact diode detector whose output is observed on a spectrum analyzer. The beat frequency between these laser emissions is subsequently measured and combined with the known reference frequencies to extrapolate the unknown far-infrared laser frequency. The resulting one-sigma fractional uncertainty for laser frequencies measured with this technique is ± 5 parts in 10 7. Accurately determining the frequency of far-infrared laser emissions is critical as they are often used as a reference for other measurements, as in the high-resolution spectroscopic investigations of free radicals using laser magnetic resonance. As part of this investigation, difluoromethane, CH 2 F 2 , was used as the far-infrared laser medium. In all, eight far-infrared laser frequencies were measured for the first time with frequencies ranging from 0.359 to 1.273 THz. Three of these laser emissions were discovered during this investigation and are reported with their optimal operating pressure, polarization with respect to the CO 2 pump laser, and strength. Video LinkThe video component of this article can be found at

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Power Measurements

Douglas¹

1989

Millimetre and Submillimetre Wavelength Lasers

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The Optically Pumped Difluoromethane Far-Infrared Laser

Cited by 7 publications

References 16 publications

Physics of high-energy heavy-ion collisions

Physics of high-energy heavy-ion collisions

Characterizing Far-infrared Laser Emissions and the Measurement of Their Frequencies

Power Measurements

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