Device for realizing orthogonal circularly-polarized light CPT atomic clock physical system

Abstract

The invention discloses a device for realizing an orthogonal circularly-polarized light CPT atomic clock physical system. The device comprises a laser beam emitting device, an attenuation sheet, a first lambda / 4 wave plate, a bubble, a second lambda / 4 wave plate, a lens, a reflector and a photoelectric detector, wherein after linearly-polarized circular emitted light emitted by the laser beam emitting device passes through the attenuation sheet, the first lambda / 4 wave plate, the bubble and the second lambda / 4 wave plate, second linearly-polarized transmitted light is obtained; the second linearly-polarized transmitted light turns into linearly-polarized parallel light after passing through the lens; after the linearly-polarized parallel light passes through the reflector, one part is transmitted into the photoelectric detector for detection, and the other part is reflected to obtain first linearly-polarized reflected parallel light; the first linearly-polarized reflected parallel light is focused by the lens to become first linearly-polarized reflected converging light; and the first linearly-polarized reflected converging light turns into third linearly-polarized reflected converging light after passing through the second lambda / 4 wave plate, the bubble, the first lambda / 4 wave plate and the attenuation sheet, and the third linearly-polarized reflected converging light is injected into a vertical cavity surface emitting laser device. Through the device, atoms can be centralized at an "0-0 energy level", so that a CPT signal is enhanced, the signal contrast ratio is increased, and microwave power is lowered.

Description

technical field [0001] The invention relates to the technical field of atomic clocks, in particular to a device for realizing the physical system of an orthogonal circularly polarized light CPT atomic clock, which is suitable for small passive CPT atomic clocks. Background technique [0002] Atomic clocks, which use quantum transitions between different energy levels of atoms to measure time, are widely used in global positioning systems, communications, and military affairs because of their ability to provide precise time. The physical system in the atomic clock is the core component of the atomic clock. The quality of the physical system directly determines the performance and indicators of the atomic clock. Therefore, the design of the physical system is one of the keys to the realization of the atomic clock. [0003] The core device of the physical system is the atomic bubble, which contains alkali metal atoms and buffer gas. Fluorescence quenching, etc. Such as figur...

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Problems solved by technology

[0006] Above-mentioned traditional passive type CPT atomic clock physical system device ( figure 2 shown) although the optical path is simple, but the light source is a single left-handed (or right-handed) circularly polarized light, so that most of the atoms accumulate on the sub-energy level with the smallest (or largest) magnetic quantum number in the ground state, and the atoms at this energy level cannot be used for CPT resonance, we call this state the "leaky" state, figure 1 Taking the rubidium 85 atom as an example, this phenomenon is illustrated, so the signal contrast (the amplitude of the photocurrent signal increased by CPT resonance is higher than that of the non-resonant photocurrent signal) is not high

However, the short-term frequency stability of an atomic clock is inversely proportional to the contrast, so the short-term stability of the atomic clock manufactured by this scheme is not high

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