Study On Blackbody Radiation Shift In Ytterbium Optical Lattice Clocks

Blackbody radiation (BBR) at any nonzero temperature will cause small shifts of atomic energy level. Blackbody radiation shift (BBRS) engenders for the reason that the two energy levels of clock transition have different frequency shifts due to BBR at room temperature. In order to realize the fractional uncertainty of10-16, we have to solve this problem. Therefore, BBRS must be suppressed by certain methods, which are as follows:First, optical lattice where Yb atoms are trapped is created by759nm laser. And then by moving the optical lattice, the atoms are transported from MOT into the cryogenic cavity. Interrogate atoms at cryogenic temperature will greatly decrease the interferences from outer environment. As a result, the uncertainty of Yb atoms optical clock caused by BBRS is reduced. In order to manipulate ultracold Yb atoms efficiently,759nm optical lattice laser of high power and narrow line width is required. To achieve this goal, our work is carried out in two aspects. First, on the experimental level, injection locking technique is introduced to get the laser, the details of which go like this. Line width of759nm master laser is1MHz, maximum output power is100mW. The output power of pump laser can reach15W. The ring cavity is chosen and the Ti sapphire crystal acts as the medium gain. Also, the Pound-Drever-Hall technique is taken to stabilize the frequency. Using the device above, we can get the759nm laser with high power and narrow line width. Second, on the theoretical level, theoretical analyses are made on the following aspects:detuning of moving optical lattice, axial and radial vibration frequencies, potential depth and the bad effects of a radial mismatch of the two waist positions. To sum up, our work will lay a foundation for the future experiment on eliminating the BBRS of the Yb atomic clock.