Use of cavity as a multipass system in laser isotope separation

It is proposed to use a multipass cavity to increase the efficiency of multistage selective photoionisation of atomic vapours. A simple analytic model is used to describe the efficiency of utilisation of radiation in a zero-dimensional cavity filled with a two-level absorbing medium. A numerical calculation is made of the kinetics of multistage selective ionisation of ¹⁶⁸Yb in a zero-dimensional cavity, taking account of 10 energy levels of different isotopes. It is shown that the use of a cavity can increase the yield of the selectively ionised isotope by an order of magnitude.