Laser transition in atomic iodine for passive and active SETI
It is proposed to use the wavelength 1.315 μm of the laser transition 2P 1/2→ 2P 3/2 in atomic iodine both for passive and active SETI. The search for an extraterrestrial signal at this wavelength is promising because an active quantum filter (AQF) with a quantum sensitivity limit and with strong fi...
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Veröffentlicht in: | Acta astronautica 2010-12, Vol.67 (11), p.1384-1390 |
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Hauptverfasser: | , , , |
Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | It is proposed to use the wavelength 1.315
μm of the laser transition
2P
1/2→
2P
3/2 in atomic iodine both for passive and active SETI. The search for an extraterrestrial signal at this wavelength is promising because an active quantum filter (AQF) with a quantum sensitivity limit and with strong fixing in the spectrum luminescence line of the width less than 0.01
cm
−1, has been developed for the noted wavelength. Such AQF is capable of receiving the laser signals, consisting of only a few photons, against the background of emission from a star under study. In addition, the high-energy iodine lasers emitting diffraction-limited nanosecond pulses of energy of 2
kJ in a single beam at the wavelength 1.315
μm have been created. The spectral tuning of radiation of these lasers allows one to compensate the frequency Doppler shift. A weak absorption of the 1.315
μm radiation in the Earth atmosphere allows the search for extraterrestrial signals by using the ground optical telescopes equipped with adaptive optical systems. |
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ISSN: | 0094-5765 1879-2030 |
DOI: | 10.1016/j.actaastro.2010.02.002 |