Abstract

In our experiments we used metastable argon. A standing light wave (light crystal) was formed using the open 801nm transition. A spontaneous decay from the excited state leads with 72% to the ground state which is not detected and hence could be regarded as being absorbed (state selective measurement). The real part of the refraction index for atoms is given by the light shift potential. The optical pumping rate to the ground state gives the absorption rate and hence the imaginary part. Tuning the laser exact on resonance the optical pumping is maximal for a given laser intensity and the light shift potential is zero. For this case a pure absorptive light crystal could be realized. Detuning the laser to the blue a light shift potential (phase crystal) arises which is in phase with the absorption. Detuning the laser to the red the phase crystal is π out of phase with the absorption crystal.

© 1996 IEEE