Generation of phase-locked beams by injection locking of extended-cavity diode lasers for atom interferometers

We report a novel method of generation of two phase-locked beams with a frequency offset at 6.834 GHz. The output of a master laser is modulated by an EOM and further injected into a slave laser that is an extended-cavity diode laser (ECDL). The ECDL amplifies laser power, and filters out unwanted modes (mostly the opposite sideband and the carrier mode) which could interfere Raman transitions and cause laser power fluctuations due to interference effect with the master laser. By injection locking, the slave laser to the first-order sideband of the modulated master laser beam, we achieve a phase noise below − 50 dBc/Hz at the frequency range between 10 Hz and 100 kHz. The generated phase-locked beams are applicable to light pulse atom interferometers as the Raman lasers.