Double photon excitation of high-rydberg atoms as a long-lived submillimeter detector
AssigneeThe United States of America as represented by the Administrator of the National Aeronautics and Space Administration
InventorAra N. Chutjian
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Abstract
A method and apparatus for detecting submillimeter or IR radiation is disclosed. A rare gas, such as xenon, is supplied at its ground state via a pressurized cylinder and an adjustable leak valve into a cryogenically-cooled detection area. The ground state of xenon is double-photon excited to a particularized level of the Rydberg series by a resonance lamp and a laser. The doubly-excited gas is then further excited by the radiation to be measured. A field ionization and an ion measurement indicative of the radiation intensity is achieved.
Claims13
A method of submillimeter detection comprising the steps of:
- metering a quantity of rare gas from a pressurized cylinder into a cryogenically-cooled detection area;
- photon exciting the rare gas atom by first subjecting it to a resonance lamp beam selected from the same rare gas;
- causing a second photon excitation of the excited rare gas atom by subjecting it to a wavelength-tunable laser beam;
- fully exciting the double-photon excited atom, by admitting into the detection area, a source of IR or submillimeter radiation to be measured;
- impressing an ionization electric field across the fully excited atom;
- and
- detecting the ion created by the field ionization as a measurement of the intensity of the submillimeter or IR irradiation.
A sumbillimeter detector comprising:
- a pressurized cylinder containing a predetermined quantitiy of a rare gas such as xenon;
- means for supplying a quantity of rare gas into a cryogenically-cooled detection area;
- resonance lamp means for photonexciting the rare gas atom by subjecting it to a beam selected from the same rare gas;
- a wavelength-tunable laser means for further photon-exciting the first excited rare gas atom;
- means admitting into the doublephoton-excited atom area a source of IR or submillimeter radiation to be measured for fully exciting the rare gas atom;
- means for applying an ionization electric field across the excited atom;
- and
- detecting means responsive to the ion created by the field ionization for measuring the intensity of said radiation.
Dependencies are inferred from the claim text.