Hyeonjae Kim

Quantum sensors using atomic vapor cells are widely investigated in the defense sector due to their compact size, lightweight and low power consumption. The selection of alkali atom, buffer gas, and cell shape and material is determined by the specific application. To ensure long-term high sensitivity in atom-based sensors, optimizing buffer gas pressure and continuously monitoring the alkali atom density inside the cell are essential. In this study, we present two applications of linear absorption spectroscopy in rubidium vapor cells: measuring buffer gas pressure and estimating the cell lifetime. In both cases, the absorption spectrum of the rubidium D1 line is measured and compared with profiles derived from theoretical calculations. The buffer gas pressure in enriched 87Rb cells with N2, used in atomic magnetometers, is determined by peak linewidth broadening and frequency shifts caused by collisions between 87Rb and N2. The lifetime of a natural rubidium cell is evaluated by periodically monitoring the rubidium number density inside the cell over time.