Transparency and parametric generation in a four-level system

摘要

We analyse two distinct nonlinear phenomena in a four-level quantum system having a tripod configuration. First, we show that the system can become transparent at two different frequencies of a probe laser field. The potential for parametric generation in this medium is also investigated. We show that, if the system is prepared in a coherent superposition of two or three of the lower levels, one or two new fields can be generated.