Figure P.1 shows two identical concave spherical mirrors forming a so-called confocal cavi...

Figure P.1 shows two identical concave spherical mirrors forming a so-called confocal cavity. Show, without first specifying the value of d, that after traversing the cavity two times the system matrix is

Then for the specific case of d =r show that after four reflections the system is back where it started and the light will retrace its original path.

Figure P.1