In the context of spectral optics, which indices are used in the reflection loss equation?

In the context of spectral optics, which indices are used in the reflection loss equation?

• A. n1 and n2
• B. n2 and n3
• C. n1 and n3
• D. n3 and n4

Answer: (A)

Reflection at an interface is determined by the refractive indices of the two media on either side of that boundary. For normal incidence, the reflectance is given by R = ((n1 − n2)/(n1 + n2))^2, so only the indices of the two adjacent media matter. That means the indices used in the reflection loss equation are the refractive indices of the incident medium and the adjacent medium, commonly labeled n1 and n2. If you have additional layers, those higher indices (like n3, n4) would come into play at other boundaries, but not in this specific boundary’s equation.

Reflection at an interface is determined by the refractive indices of the two media on either side of that boundary. For normal incidence, the reflectance is given by R = ((n1 − n2)/(n1 + n2))^2, so only the indices of the two adjacent media matter. That means the indices used in the reflection loss equation are the refractive indices of the incident medium and the adjacent medium, commonly labeled n1 and n2. If you have additional layers, those higher indices (like n3, n4) would come into play at other boundaries, but not in this specific boundary’s equation.