Power Broadening of Two-Photon Coherent Resonances on Rydberg Atomic Transitions in a Magneto-Optical Trap

We study power broadening of coherent two-photon resonances on Rydberg transitions in lithium-7 atoms in a magneto-optical trap (MOT). We apply the spectroscopic technique based on the reduction of resonance fluorescence in the MOT. One of the main contributions to the spectral broadening is associated with heating of the trapped atoms by laser cooling beams. We suggest a new nondestructive method to measure the atomic temperature in a working MOT using two-photon spectroscopy with variable directions of probe beams.