Miniature gas cell with folded optics

In an atomic frequency standard containing an optically reactive gas, the improvement comprising means for providing multiple light paths through said optically reactive gas, including a concentrically assembled semiconductor laser and photodetector and a reflective surface, with a closed gas cell containing said optically reactive gas therebetween, said gas cell having dimensions such that divergent light of said laser optimally impinges on said photodetector.

In an atomic magnetometer containing an optically reactive gas, the improvement comprising a means for providing multiple light paths through said optically reactive gas, including concentrically assembled semiconductor laser/photodetector devices and a reflective surface, with a closed gas cell containing the optically reactive gas, therebetween, said gas cell having dimensions such that divergent light of said laser optimally impinges on said photodetector.

A gas cell for interrogation of an atomic gas, comprising

• means forming a closed gas cell containing the atomic gas,
• said means carrying a light source and a light sensor formed on a single substrate, and further carrying a light reflective surface, said light source, fight reflective surface, and light sensor forming a multiple light path through the atomic gas in said closed gas cell,
• light from said light source traveling through the closed gas cell and being reflected from said light reflective surface to said light sensor.

Means forming a gas cell for an atomic frequency standard, said means comprising

• a cup-shaped glass container forming the periphery and one end of the gas cell, said one end of the gas cell carrying a light reflective surface, and an integrated heater and temperature sensor,
• a glass window sealed with the periphery of the cup-shaped glass container, closing and forming the other end of the gas container,
• a single chip formed with a semiconductor laser diode and a photodetector carried by said glass window, said single chip and said light reflective surface being spaced by said cup-shaped container so light from the semiconductor laser diode can be directed at said light reflective surface and reflected from said light reflective surface to optimally impinge on said photodetector.

In a CPT atomic frequency standard including a closed gas cell containing an atomic gas, the improvement comprising

• means forming a multiple path for light through the atomic gas, including a concentrically assembled light source and light detector, and a light reflective surface, and
• a circular polarizer for the light from said light source, said circularly polarized light traveling through the atomic gas in said gas cell and being reflected from said light reflective surface to said light detector.