Prospect of optical frequency standard based on a ⁴³Ca⁺ ion

An optical frequency standard based on the S-D transition of trapped ⁴³Ca⁺ is possible by using just laser diodes for cooling and probing. We discuss two open problems related to the feasibility of this frequency standard, the attainable frequency uncertainty and the method of initial-state preparation. The uncertainty of the clock transition frequency can be so small as 1×10⁻¹⁵ . Using a laser system consisting of three lasers at different detunings and polarizations, the ion can be cooled down to the Lamb-Dicke regime and then prepared in the m=0 state within a period much shorter than the cooling period without being heated. The details of our numerical simulation are described.