The 180 degree phase shift only occurs from lower index of refraction material (air) to higher index of refraction material (coating). If you have n_airn_glass, we do not get the additional 180 degree phase shift, so only a 360 degree phase shift - thus, the original light (phase shift 180 degrees) and the transmitted-reflected light (phase shift 360 degrees) destructively interfere since their phase difference is 180 degrees. You can try and think bout what a reflecting coating would work like. In this case we want the original light reflected off of the air-coating interface to constructively interfere with the transmitted and then reflected coating-glass light. So here's the same example as the first: n_air
Can someone please help me? Why does anti reflection coating of lenses have to be a quarter of the wavelength of light, if both of the reflected waves (from the first surface and the second surface) will undergo 180 degree phase change? Won't they interfere constructively in any way, despite the thickness of the coating, since the reflected rays will be exactly the same as the incident wave, except they BOTH will be 'flipped upside down', having the same phase (no phase change between the two reflected waves)? Both of the reflected waves should undergo 180 degree phase change and therefore, interfere constructively.
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The 180 degree phase shift only occurs from lower index of refraction material (air) to higher index of refraction material (coating). If you have n_airn_glass, we do not get the additional 180 degree phase shift, so only a 360 degree phase shift
- thus, the original light (phase shift 180 degrees) and the transmitted-reflected light (phase shift 360 degrees) destructively interfere since their phase difference is 180 degrees.
You can try and think bout what a reflecting coating would work like. In this case we want the original light reflected off of the air-coating interface to constructively interfere with the transmitted and then reflected coating-glass light.
So here's the same example as the first: n_air
legend - thank you for the explanation !!
AMAZING VIDEO
Can someone please help me? Why does anti reflection coating of lenses have to be a quarter of the wavelength of light, if both of the reflected waves (from the first surface and the second surface) will undergo 180 degree phase change? Won't they interfere constructively in any way, despite the thickness of the coating, since the reflected rays will be exactly the same as the incident wave, except they BOTH will be 'flipped upside down', having the same phase (no phase change between the two reflected waves)? Both of the reflected waves should undergo 180 degree phase change and therefore, interfere constructively.
did u get an answer?