Experimental realization of strong coupling between a cold atomic ensemble and an optical fiber microcavity

The cavity quantum electrodynamics (QED) system is a promising platform for optics and information experiments. Its core the strong coupling between atoms optical cavity, which causes difficulty in overlap antinode of mode. Here, we use programmable movable dipole trap to load cold atomic ensemble into an fiber microcavity realize strength can be improved by polarization gradient cooling adiabatic loading. By measurement vacuum Rabi splitting, as high gN=2π×400 MHz, means effective atom number Neff=16 collective cooperativity CN=1466. These results show that this experimental used molecule based QED research.