Wave Optics31324.17With and coatingaircoatinglensnn>2coatingntm, light reflecting at the air-coating boundary experiences a phase reversal, but light reflecting from the coating-lens boundary does not. Therefore, the condition for destructive interference in the two reflected waves is >λ=where 0, 1, 2,m=…For finite wavelengths, the lowest allowed value of mis m1=. Then, if , the wavelength associated with this lowest order destructive interference is 177.4 nm and 1.55coatingtn==()( )121coatingnt2 1.55177.4 nm550 nm=24.18 Since , light reflected from both top and bottom surfaces of the oil film experiences phase reversal, resulting in zero net phase difference due to reflections. Therefore, the condition for constructive interference in reflected light is airoilwaternnn<<2nfilmtmmn, or 2filmn
This is the end of the preview. Sign up
access the rest of the document.