Abstract
Index of refraction characterizes the linear response of a medium and hence it is strongly enhanced near atomic resonance. However, it is accompanied by either resonant absorption or gain preventing the use of high index. We show that these problems may be overcome using coherent control of excited state absorption (ESA), i.e. absorption from the populated excited electronic state. The idea is to compensate gain at the lower operating transition via partially suppressed ESA at the frequency of the probe field tuned to the maximum refractive index of the ESA transition. It results in resonant enhancement of refractive index without absorption in the absence of any neighboring amplification regions.