Cost-effective magneto-optical trap of ytterbium atoms

We report on a cost-effective magneto-optical trap (MOT) of ytterbium atoms by using diode lasers as a previous step for an optical lattice clock. For the purpose of MOT, we have specially designed GaN external cavity laser diodes (ECLD), which outputs 10 mW at a wavelength of 399 nm. One of the ECLD is used to trap the ytterbium atoms along x-axis, while additional F-P diode lasers, which is injection locked to the previous ECLD, is used for the trapping along y and z axes. These trapping lasers are frequency stabilized to Doppler free $^{1}$S$_{0}-^{1}$P$_{1}$ transition. We have trapped 5$\times $10$^{6}$ atoms for $^{174}$Yb and 2$\times $10$^{6}$ atoms for $^{171}$Yb respectably at a trapping temperature of 1 mK, which is still too high for settling the atoms inside the optical lattice. In order to further decrease the trapping temperature an additional cooling laser is necessary corresponding to $^{1}$S$_{0}-^{3}$P$_{1}$ transition with which ytterbium atoms can be cooled to 4 $\mu $K. To obtain the desired laser, 1112 nm ECLD with 200 mW output is frequency doubled through MgO doped PPLN waveguide.