Role of incoherent pumping and Er<sup>3+</sup> ion concentration on subluminal and superluminal light propagation in Er<sup>3+</sup>-doped YAG crystal

Role of incoherent pumping and Er³⁺ ion concentration on subluminal and superluminal light propagation in Er³⁺-doped YAG crystal

Asadpour Seyyed Hossein†, Soleimani H. Rahimpour

Fig.#cod#x00A0;1. Er 3+ :YAG crystal interacting with two laser fields and an incoherent field. Probe field couples |1#cod#x27E9; #cod#x2194;| 4#cod#x27E9; transition, and control field drives |1#cod#x27E9; #cod#x2194;|3#cod#x27E9; transition. An incoherent pump field with the pumping rate r acts on |2#cod#x27E9; #cod#x2194;|4#cod#x27E9; transition. [ 68 ]