What is the minimum thickness of a nonreflecting film coating (n = 1.30) on a glass lens (n = 1.50) for wavelength 500 nm?
A) 250 nm
B) 221 nm
C) 192 nm
D) 167 nm
E) 96.2 nm

Question

Quizplus · Accepted Answer

The minimum thickness for destructive interference in a nonreflecting film is given by $ t = \frac{\lambda}{4n} $. For a wavelength of 500 nm and film index of refraction $ n = 1.30 $, the thickness is $ t = \frac{500}{4 \times 1.30} \approx 96.2 $ nm.

What Is the Minimum Thickness of a Nonreflecting Film Coating