H1 The time-averaged intensity for light composed of parallel wave vectors is well-approximated by: I(F,t) = neoC 2 - E(F, t ) . E (F, t ) If we superimpose two waves then: E(7, t ) = E(F, t) + Ez(F, t ) Where El(F, t) = Eve (kif wit) and E2( 7, t ) = Eve (kyr-wat ) a) In the slowly varying regime: meaning one can neglect oscillating frequency terms greater than @ and/or wz show that I(F, t) = noCE. . E; [1 + cos(Ak . F - Aut)] where AK = ka - ki and Aw = w2 - WI Remember that -18 cos d =