A 408 nm Laser System to Drive Stimulated Raman Transitions

We will discuss a diode laser system that produces two laser beams, differing in frequency by 1 GHz, that can be used to drive Raman transitions in $^{87}$Sr$^+$. This system will be used to generate the $\pi$ and $\pi/2$ pulses in an ion interferometer. The laser consists of a grating stabilized master laser. This is then passed through an AOM and retroreflected back through the AOM in order to provide two frequency-shifted beams. These beams are then used to injection lock two slave lasers, in a scheme similar to the one described in [1]. The AOM can be modulated with a stability better than 1 Hz. Thus we guarantee that the light output from the slaves is at a constant detuning, while drift from the master laser corresponds to common mode drift (to which the Raman transition is less sensitive). We will also discuss a technique used to improve laser stability similar to the scheme described in [2] but using the measured impedance of the diode rather than the amplitude noise on the light to generate an error signal. \\[4pt] [1] P. Bouyer, T. L. Gustavson, K. G. Haritos, and M. A. Kasevich, Optics Letters 21, 1502-1504 (1996)\\[0pt] [2] Sheng-wey Chiow, Quan Long, Christoph Vo, Holger M\"uller, and Steven Chu, Applied Optics 46, 7997-8001 (2007)