Atomic oscillator

Abstract

The invention provides an atomic oscillator which improves S / N by improving energy level of light absorbed by a photodetector. The atomic oscillator (50) mainly includes a cell (2) containing a mixture gas of alkali metal atoms and isotopes of the alkali metal atoms, a light source (LD) (1) that has coherency and irradiates the gas with lights including a first resonant light pair having two different frequency components for one center frequency and a second resonant light pair having two different frequency components for one center frequency, a photo detector (PD) (3) that generates a detection signal corresponding to intensity of light passing through the gas, and a frequency control part (12) that controls, based on the detection signal, frequencies of the first resonant light pair to cause an electromagnetically induced transparency phenomenon to occur in the alkali metal atom and controls frequencies of the second resonant light pair to cause the electromagnetically induced transparency phenomenon to occur in the isotope of the alkali metal atom.

Description

technical field [0001] The present invention relates to a method of controlling a light source of an atomic oscillator, and more particularly, to a light source of an atomic oscillator for stabilizing absorption trapping due to variable absorption gain of the atomic oscillator method of control. Background technique [0002] The atomic oscillator applying the electromagnetically induced transparency method (also called the EIT (Electromagnetically Induced Transparency) method, CPT (Coherent Population Trapping) method) is an oscillator that utilizes the following phenomenon (EIT phenomenon), that is, when the base When metal atoms are simultaneously irradiated with two types of resonance light having different wavelengths, the absorption of the two types of resonance light stops. Therefore, it is very important to obtain the EIT phenomenon stably. [0003] It is known that the interaction mechanism between the alkali metal atom and the two resonant lights can be as Figure...

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Problems solved by technology

[0006] However, the prior art disclosed in Patent Document 1, such as Figure 7 As shown in (B), by the frequency f generated by the current drive circuit 0 (=v / λ 0 : v is the speed of light, λ 0 is the central wavelength of the laser), the drive current is equivalent to the energy difference ΔE between the first ground state energy level 33 and the second ground state energy level 34 12 The modulation frequency fm1 of 1 / 2 of the frequency is modulated, so that the semiconductor laser produces a frequency of f1=f 0 The first resonant light 31 and frequency of +fm1 are f2=f 0 The second resonant light 32 of -fm1 causes the gaseous alkali metal atoms contained in the atomization cell to generate the EIT phenomenon

In addition, although in the EIT phenomenon, the greater the number of alkali metal atoms contained in the atomization cell, the greater the number of atoms contributing to the EIT phenomenon, and thus the greater the energy level of light that can be detected by the photodetector , but due to the demand for miniaturization and low consumption in recent years, when the number of alkali metal atoms contained in the atomization pool decreases, the number of atoms that contribute to the EIT phenomenon will also decrease, and there will be detected The problem that the energy level of light decreases and causes S / N deterioration

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