Optimized acousto-optic modulation for the V-type electromagnetically induced transparency in rubidium-87 D1 line

Abstract

We present an experimental setup of optimized acousto-optic modulator designed for observing a V-type electromagnetically induced transparency resonance in the D1 line of rubidium-87, with the full width at half maximum being equal to 2.7 MHz. Possible artefacts and undesirable influences on the signal resulting from this method are discussed in detail. The solutions to such technical challenges as beam steering and intensity fluctuations are found in optimization of optical setup. The reported method offers a number of advantages such a single external-cavity diode laser to create a bichromatic optical field outside the laser, whereby both the coupling and probe beams have identical properties. Moreover, the both beams are equally affected by environmental perturbations to the laser. Subsequently, the influence of mode hopping, beam-power fluctuation and frequency drift on the resonance can be eliminated. This negates a need in complicated and expensive temperature and current stabilizations, as well as in a locking unit. The simplicity and stability of the improved setup make our method suitable for many applications based upon electromagnetically induced transparency, especially those in the field of precision measurements.