NASA Technical Reports Server (NTRS) : Method pdf

NASA Technical Reports Server (NTRS) : Method

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Helium in the superfluid state emits copious amounts of radiation in the ultraviolet region when excited by an electron stream. Conventional laser action using mirrors is impossible in superfluid helium because there are no mirrors that will reflect VUV radiation. By utilizing the distributed feedback method, the superfluid helium can be made to lase. By setting up a standing wave in superfluid helium that has a wavelength equal to, or harmonically related to, half the wavelength of the photon radiation chosen to be emitted as laser radiation by the superfluid helium, the need for end mirrors to produce reflection of the laser radiation is eliminated and reflection occurs instead at the wavefronts of the standing wave. The photons leave the superfluid helium at right angles to the standing wave as coherent radiation having a very high intensity. The standing wave established in the superfluid helium may be an acoustical standing wave, a thermal standing wave (second sound), or an electric standing wave

• Creator/s: NASA Technical Reports Server (NTRS
• Date: 7/27/1976
• Year: 1976
• Book Topics/Themes: NASA Technical Reports Server (NTRS), COHERENT RADIATION, HELIUM, LASERS, SUPERFLUIDITY, ULTRAVIOLET RADIATION, ELASTIC WAVES, ELECTRON BOMBARDMENT, FEEDBACK, MIRRORS, STANDING WAVES, WAVE REFLECTION, Saffren, M. M. [Inventor

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