  Single and double electromagnetically induced transparency (EIT) in a medium,
consisting of four-level atoms in the inverted-Y configuration, are discussed
using mechanical and electrical analogies. A three coupled spring-mass system
subject to damping and driven by an external force is used to represent the
four-level atom mechanically. The equations of motion of this system are solved
analytically, which revealed single and double EIT. On the other hand, three
coupled RLC circuits are used, as the electrical analog, to explore and
experimentally demonstrate single and double EIT. The simplicity of these two
models makes this experiment appropriate for undergraduate students and easy to
incorporate into a college physics laboratory.
