Coherent Population Trapping Based Atomic Sensors for Space Application

Abstract

Coherent population trapping (CPT) is a promising technique to realize miniaturized atomic frequency standard (clocks) and magnetic field sensor (magnetometer) for precision measurements in space. Atomic clocks in particular are the reference source for precision time and frequency signals in navigational satellites. Frequency stability of atomic clocks and sensitivity of magnetometer depend primarily on the quality factor of CPT resonance which is the function of amplitude (contrast) and line width ( $$\Delta \nu_{{\text{FWHM}}}$$ ). In this paper, the CPT resonance characteristics are studied with respect to various critical operating parameters such as laser excitation intensity (atomic excitation), cell temperature, and radio frequency (RF) power. Our study shows that FWHM increases linearly with laser intensity, whereas resonance signal contrast increases with cell temperature up to an optimum temperature and then after decreases with increase in temperature. The numerical values for these operating parameters are then derived by analyzing the experimental results and then arrived at an optimized quality factor for the atomic system.