4 of 7 Ήι ER ns HT Z nu ET Transverse Electric, TE The Figure above shows TE polarised light incident on a dielectric interface. Light is in- cident from the upper left, in a sourced medium with refractive index ns at an angle of incidence 01, onto an unsourced medium with refractive index nu, and transmitted at angle of refraction T. Both media are non-magnetic. The vectors HI, HR, HT are the magnetic fields for incident, reflected and transmitted waves respectively; the corresponding E fields point into the paper, as shown by the arrow-tail symbols. State the boundary conditions on the E and H fields, then use these to prove that the amplitude transmission coefficient tTE is given by 2ns cos 01 ET tTE= Ει ns cos 01 nu COS OT (Justify any assumption relating impedance to refractive index).

4 of 7 Ήι ER ns HT Z nu ET Transverse Electric, TE The Figure above shows TE polarised light incident on a dielectric interface. Light is in- cident from the upper left, in a sourced medium with refractive index ns at an angle of incidence 01, onto an unsourced medium with refractive index nu, and transmitted at angle of refraction T. Both media are non-magnetic. The vectors HI, HR, HT are the magnetic fields for incident, reflected and transmitted waves respectively; the corresponding E fields point into the paper, as shown by the arrow-tail symbols. State the boundary conditions on the E and H fields, then use these to prove that the amplitude transmission coefficient tTE is given by 2ns cos 01 ET tTE= Ει ns cos 01 nu COS OT (Justify any assumption relating impedance to refractive index).