An Efficient Method for Measuring Spin Relaxation Time Based on Electromagnetically Induced Transparency

Atomic precision measurement technologies based on the Spin-Exchange Relaxation-Free (SERF) regime play a vital role in advanced research and the relaxation characteristics of the vapor cell are key factors that determine the sensitivity and stability of measurements. As a result, the accurate measurement of relaxation time has become an important research focus. In this work, a novel and efficient method is proposed for measuring relaxation time based on the technique of Electromagnetically Induced Transparency (EIT), and validate it experimentally under both geomagnetic and magnetically shielded conditions. By utilizing the D1 transition line of ⁸⁷Rb atoms, a three-level (Formula presented.) -type EIT system is constructed. An optical setup is developed, incorporating a specially designed light source, vapor cell, temperature-controlled heating structure, and magnetic shielding. After turning off the coupling beam, the relaxation characteristics are obtained by measuring the transmission spectrum of the probe beam. Under geomagnetic conditions, the fitted fast and slow relaxation times are 0.56 and 105.67 ms, respectively; under magnetic shielding, the corresponding values are 47.88 and 100.32 ms. Furthermore, the influence of temperature and coupling beam power on the relaxation process is investigated, providing theoretical insight for improving the performance of atomic precision measurement technologies.