Seeing through electromagnetically induced transparency

Electromagnetically controlling transparency is important for fast optical switching and sensitive metrology and is usually ascribed to coherent population trapping. On the hand Autler-Townes splitting also describes electromagnetically induced transparency for a strong pump. Fully classical versions of electromagnetically induced transparency are also reported. Variants arise such as vacuum induced transparency. Here i explain the physics of electromagnetically induced transparency and Autler-Townes splitting and how discern between them and show how effective classical coupled oscillators can be at describing the phenomenon. I also show how the novel effect of electromagnetically induced transparency with amplification could be realized in superconducting circuit quantum electrodynamics.