“…The transitions |m, n 1 , n 2 â |m + 1, n 1 , n 2 , |m, n 1 + 1, n 2 â |m + 1, n 1 , n 2 , and |m, n 1 , n 2 â |m, n 1 + 1, n 2 can be achieved by applying a probe field, an optical pump field, and a mechanical pump field. Clearly, the three couplings result in a closedloop â-type transition strcture, leading to the phasesensitive optical behaviors of the OMIT system [78][79][80]. As shown in Fig.…”