A single-mode semiconductor diode laser operating in the strong optical feedback regime and tunable within the D 1 line of the Cs atom

Abstract

The importance of using the D 1 line of the Cs atom in atomic and optical physics experiments is clarified. The development of an external-cavity diode laser system suitable to excite the D 1 line of the Cs atom, which occurs at 895 nm, is presented. The laser is operated in the strong optical feedback regime. The effect of the feedback strength on the system performance is analyzed. Under the condition of strong optical feedback, a single-mode linewidth of ≈1.8 MHz, a continuous tuning range of ≈20 GHz (at the fixed angle of the grating), and a laser output power of ≈10 mW are demonstrated. Using the well-known values of the hyperfine splitting in the Cs atom, we determine the temperature and current tuning rates with an external cavity to be ≈31.5 GHz/°C and ≈0.9 GHz/mA, respectively. The laser is demonstrated to be tunable to any of the dipole-allowed hyperfine transitions within the D 1 line of the Cs atom. In addition this laser is suitable for incoherent optical pumping as required in lasing without population inversion experiments. The capability of using this laser in an electromagnetically induced transparency experiment is demonstrated.