Lanthanides Laser cooling

Electronic States of 5 Lanthanide-Doped Laser-Cooling ... 

Kastler pointed out in 1950 that lanthanide ions doped into transparent solids could be effective fluorescent coolers because they possess excited states with high quantum efficiencies (Kastler, 1950). A first experimental attempt to achieve laser cooling of a solid was undertaken by Kushida and Geusic of Bell Telephone Laboratories in 1968 (Kushida and Geusic, 1968). They used the 1064 nm hght of a Nd +-doped Y3AI5O12 (YAG Nd) laser to... 

The detailed analysis of the four-level system in Section 2.3 has shown that the laser-cooling efficiency is inversely proportional to the pump laser energy hVp (Eq. 14). This favors the use of lanthanide ions with a low energy of the first excited state. Most of the work to date has been performed on Yb -doped materials. Here, the energy separation of 9800 cm ... 

LANTHANIDE-DOPED LASER-COOLING MATERIALS 5.1 Yb +-Doped Materials... 

Fig. I. Methods for forming metal vapors, (a) Evaporation from a resistance-heated, alumina-coated Mo or W spiral. This is a method suitable for Cr, Mn, Fe, Co, Ni, Cu, Pd, Ag, Au and other metals that do not attack alumina, (b) Evaporation from a resistance-heated Ta or W boat. This method is useful for V, Cr, and some lanthanides, (c) Sublimation from a resistance-heated free-hanging loop of wire, e.g., Ti, Mo, or W. (d) Evaporation from a cooled hearth using laser or electron bombardment heating. This method may be used with all metals.

The technique for producing stationary samples of alkali atoms is a magneto-optical trap, or MOT. ° MOTs can be produced with the alkali atoms, metastable halides, some lanthanides, and several other atoms. The technique for producing a MOT relies on the atoms having closed or near closed electronic transitions at experimentally accessible laser wavelengths. With the appropriate laser and magnetic field configuration atoms can be cooled and confined with typical temperatures below 1 mK and peak densities of 10 ° atoms/cm. ... 

---