Tuesday
September 16, 2014

Homework Help: Physics

Posted by Vanda on Sunday, October 9, 2011 at 3:40pm.

Light is incident on a glass-air interface from the glass side
(n=1.5), and researchers want to use the evanescent field on the air side (n=1.0) to excite the
molecules adhered to the surface. It is desired that the evanescent field extend a distance δ = 2 Ám
into the air side when using light of free-space wavelength of 1 Ám.
a. How close to critical angle must the incident beam be? (Give the difference ∆θ = θ1 - θc)
b. Considering that a beam with finite width contains rays with a spread of angles due to diffraction,
how wide must the beam be so that the angular spread is just equal to the difference in angle
found in part a?

Answer this Question

First Name:
School Subject:
Answer:

Related Questions

Physics - When light travels from air to glass, which one of the following is ...
Physics - A prism, made of glass of refractive index 1.50, has two plane faces ...
Physics - For a piece of glass n(red)= 1.635 and n(blue)= 1.689. The respective ...
Physics - A ray of light of frequency 5.09 x 10^14 Hz passes from air into flint...
Physics - Trace by drawing the path of a ray of light shown in 90 degrees. This ...
physics - A glass plate whose index of refraction is 1.67 is immersed in a ...
physics - A glass plate whose index of refraction is 1.47 is immersed in a ...
College physics - A ray of red light, for which n=1.54, and a ray of violet ...
Physics again - The equilateral glass prism shown has an index of refraction of ...
Physics - If light in air is incident at 20░, at what angle is it refracted in ...

Search
Members