When light reflects off a nonconducting material, the reflected light is partially polarized. The amount of polarization depends on the incident angle and the index of refraction of the reflecting material. The incident angle that gives maximum polarization is called Brewster’s Angle.
Light from a diode laser (wavelength = 650 nm) is reflected off the flat side of an acrylic semicircular lens. The reflected light passes through a polarizer and is detected by a Light Sensor. The angle of incidence is measured by a Rotary Motion Sensor mounted on the spectrophotometer table. The intensity of the reflected polarized light vs. incident angle is graphed to determine the angle at which the light intensity is a minimum. This is Brewster’s Angle, which is used to calculate the index of refraction of acrylic.
Applications
- Brewster’s Angle
- Intensity of Reflected Light (Without Polarizer)
- Intensity of Transmitted Light
- Snell’s Law
How It Works
When unpolarized light reflects off a nonconducting surface, it is partially polarized parallel to the plane of the reflective surface. There is a specific angle called Brewster’s angle at which the light is 100% polarized. This occurs when the reflected ray and the refracted ray are 90 degrees apart.
Using the Brewster’s Angle Accessory, light from a diode laser with a wavelength of 650 nm is reflected off the flat side of an acrylic semi-circular lens. The reflected light passes through a polarizer and is detected by a Light Sensor. The angle of incidence is measured by a Rotary Motion Sensor mounted on the Spectrophotometer table. The intensity of the reflected polarized light versus incident angle is graphed to determine the angle at which light intensity is a minimum. That angle is Brewster’s Angle and can then be used to calculate the index of refraction of the acrylic.
What's Included
- 1x Acrylic semicircular lens
- 1x Lens platform
- 2x Polarizers with holder
- 1x Analyzing polarizer
- 1x Beam splitter
