Abstract: In an apparatus using optically excited atomic media, such as an atomic frequency standard, a source providing a controlled emission of light for exciting the D1 and/or D2 resonance lines of an alkali gas, such as rubidium or cesium, is controlled by an output generated by digital electronics from the light intensity signal of a light sensor for light transmitted by the alkali gas, an output for representing ambient temperature, and a light intensity-ambient temperature algorithm to substantially eliminate changes in light intensity due to light source aging for the purpose of reducing changes in temperature sensitivity of the apparatus as a function of time and the light-shift contribution to the frequency aging of the standard.

Abstract: A novel atomic frequency standard includes an absorption cell containing a first volume of atoms for varying an intensity of light energy passing therethrough; at least one dielectric resonator for generating an evanescent electromagnetic field that effects hyperfine energy level transitions of the first volume of atoms; a waveguide for housing the absorption cell and one or more dielectric resonator(s); a photo detector mounted near an end of the waveguide for receiving light energy; and an electromagnetic energy injector for electromagnetically exciting the dielectric resonator(s). Preferably, a filter cell is positioned adjacent to a dielectric resonator between the absorption cell and the light source.

Abstract: A method of reducing the interrogation signal phase noise in passive, compact, low-cost commercial atomic standards, particularly phase noise occurring at a Fourier frequency equal to twice the modulation frequency, 2f.sub.mod. The method involves selecting the modulation frequency so that 2f.sub.mod is on the order of, or greater than, the atomic bandwidth (full width at half maximum signal value).

Abstract: Optical pumping devices use light reflected from reflecting surfaces to provide a portion of the light incident on the photodetector. Conventional optical pumping devices experience a decay, over time, of the initial light intensity incident on the photodetector. The optical pumping device of the invention experiences reduced light intensity decay. The invention passivates the reflecting surfaces to eliminate tarnish and oxidation by pretarnishing the surfaces or covering the surfaces with a material whose reflectivity does not vary over time, such as gold.