The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 17, 1977
Filed:
May. 10, 1976
Robert M Hill, Palo Alto, CA (US);
Thomas F Gallagher, Palo Alto, CA (US);
Stanford Research Institute, Menlo Park, CA (US);
Abstract
Highly sensitive method and apparatus for photon detection in the microwave and infrared regions of the electromagnetic energy spectrum are shown in which atoms of a material in the vapor state are excited to a first Rydberg energy level by use of radiation from one or more laser beams. The Rydberg excited material is subjected to the low energy radiation to be detected to induce therein an allowed electric dipole transition from said first to a second Rydberg energy level of the same or quite similar principal quantum number. Spontaneous high energy emission as a result of a distinctive radiative transition from said second Rydberg energy level is detected independently of other radiative transitions by conventional photodetector means such as a photomultiplier operable within the optical spectrum. The photomultiplier output provides a measure of said radiation to be detected. Tuning may be provided by the application of a magnetic field of selected strength to the atoms for Zeeman splitting of the first and second Rydberg energy levels. Also, for photon detection over a range of frequencies, a space or time varying magnetic field may be employed together with suitable photodetection means.