A study of the repumping laser and external magnetic field effect on coherent absorption resonance in alkali vapour

Abstract Investigation of coherent absorption resonance via electromagnetically induced absorption (EIA) spectra in rubidium vapour has been done in presence of a repumping laser and an external magnetic field. The EIA line shape gets enhanced and symmetric with the application of the repumping laser. In presence of an external magnetic field the amplitude of the EIA resonance gradually diminishes and at higher magnetic field, two absorption dip-like structures along with a transmission peak in between is obtained. Theoretically calculated spectra based on density matrix approach show a good agreement with the observations.