Magnetic induced dichroism and frequency stabilization of violet blue diode lasers on gallium atomic transitions

We study the magnetic-field-induced dichroism on a sample of gallium neutral atoms created in a hollow cathode lamp and describe a method for robust stabilization of violet–blue diode lasers tuned on gallium atomic transitions for an atom nanofabrication experiment. We compare the experimental dichroic signals with theoretical simulations obtained by the solving of the exact atom-field interaction Hamiltonian. We find excellent agreement when considering the magnetic field shielding from the hollow cathode. This method allows for a wide range of frequency tuning, modulation-free locking, and long-term stability of external-cavity diode lasers. From analysis of a square root Allan variance we have achieved a stability of 1 MHz at 1-s average time.