An Accurate Frequency Control Method and Atomic Clock Based on Coherent Population Beating Phenomenon

Abstract

An accurate frequency control method and atomic clock based on the coherent population beating (CPB) phenomenon is implemented. In this scheme, the frequency difference of an rf and an atomic transition frequency can be digitally obtained by measuring the CPB oscillation frequency. The frequency measurement resolution of several milli-hertz can be achieved by using a 10 MHz oven controlled crystal oscillator as the reference. The expression of the Allan deviation of the CPB clock is theoretically deduced and it is revealed that the Allan deviation is inversely proportional to the signal-to-noise ratio and proportional to the line-width of coherent population trapping spectrum. We also approve that the CPB atomic clock has a large toleration of the drift of the local oscillator. In our CPB experimental system, a frequency instability of 3.0 × 10 −12 at 1000 s is observed. The important feature of high frequency measurement resolution of the CPB method may also be used in magnetometers, atomic spectroscopy, and other related research.

Analysis of iris-loaded resonance cavity in miniaturized maser*

“…Recently, there was an increasing interest in radicallyminiaturized masers such as compact rubidium masers (CRM) and passive hydrogen masers (PHM), which are used as atomic clocks in communication and localization applications. [1][2][3][4][5][6][7][8][9] Iris-loaded resonance cavity (IRC) is widely used in these masers. Compared with cylindrical cavity and sapphire-loaded cylindrical cavity, the IRC can greatly reduce the radial size of atomic clock.…”

Development of a Miniaturized Frequency Standard Comparator Based on FPGA

“…A frequency standard is a device that can provide sinusoidal signal with high accuracy and stability, and its frequency value is usually 10 MHz, although in some cases it can be 5 MHz or 1 MHz [1][2][3][4]. It is undeniable that any specific device that generates standard values is not absolutely stable, and the frequency standard is no exception.…”

Laser frequency offset-locking using electromagnetically induced transparency spectroscopy of 85 Rb in magnetic field

“…Laser beam sources with their relative frequency difference locked are important for the studies of laser-atom interactions, such as slow light, [1] lasing without inversion, [2][3][4] and atomic clocks. [5][6][7][8] These laser sources needed for experiments can be obtained from a single laser beam or two/multi different laser beams. The simplest approach is to employ an acoustooptical modulator (AOM), [9] or an electro-optical modulator (EOM), [10] or to directly modulate the driving current of a diode laser.…”