Physics Help Forum Beamsplitter Intensities
 Nov 4th 2010, 09:06 PM #1 Junior Member   Join Date: May 2008 Posts: 29 Beamsplitter Intensities In this problem, light is incident on a beamsplitter, and then it travels around loops of optical fibre before eventually coming out the other end. I needed to find the intensities of E1 and E2. (Attached image) This is what I did: Let $E_a=-rE_{in}$ be the reflected light from E_{in} and let $E_b=tE_{in}$ be the transmitted light. Also let "delta" be the phase the light travels through in the loops of optical fibre. Then $E_1=tE_ae^{i\delta}-rE_be^{i\delta}=-rtE_{in}e^{i\delta}-rtE_{in}e^{i\delta}=-2rtE_{in}e^{i\delta}$ And $E_2=-rE_a e^{i\delta}+tE_be^{i\delta}=(r^2+t^2)E_{in}e^{i\delta}$ But the Question says that "you should find all light reflected back to the output", meaning E2=0! What have I done wrong? Thanks Attached Thumbnails   Last edited by DivideBy0; Nov 4th 2010 at 09:31 PM.