Optical lattice in a high-finesse ring resonator

An one-dimensional optical lattice with rubidium atoms ${(}^{85}\mathrm{Rb})$ is formed inside a ring resonator with a finesse of $1.8\times {10}^5$ and a large mode volume of $2.6{\mathrm{mm}}^3.$ We typically trap several times ${10}^6$ atoms at densities up to ${10}^{12}{\mathrm{cm}}^{-3}$ and temperatures between 25 and $125\mu \mathrm{K}.$ Despite of the narrow bandwidth (17.3 kHz) of the cavity, heating due to intracavity intensity fluctuations is kept at a low level, such that the time evolution of the temperature is determined by evaporative cooling.