laser

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Laser light bend

laser bend

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  • Tank shown above contains a solution of sugar water that becomes more and more concentrated with depth. As sugar water has a higher index of refraction than pure water, the sugar density gradient produces a depth-dependent index of refraction. A laser beam shot through the solution, initially parallel to the bottom of the tank, will bend downward and hit the bottom.
  • To prepare solution: pour sugar into empty tank, a few centimeters thick. Then, using a hose, very slowly (so as not to agitate sugar) fill the tank with water about halfway full.
  • Tank located in L01, section B6. Sugar in L35, under sink. Laser in L35, section A5.
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Tonic Water Fluorescence

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Light, of high enough frequency, will cause quinine (found in tonic water) to fluoresce. The emitted light is a brilliant blue color. Also works with a black light.

Location:  Tonic water and violet laser pointer in L01, section B4. Black light in section A1 (or A2).

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Refraction with Water

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laser refraction 1

laser refraction 2

total internal reflection

  • Refracted beam of light made visible with water, coffee creamer, and smoke.
  • Fill container half way with water. Mix in 1 or 2 pinches of non-dairy coffee creamer.
  • Use smoke maker (blue device in top photo) to fill container with smoke. Place lid on container to contain smoke.
  • Use laser pointer to create beam of light.

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Poisson Spot

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  • Shine coherent light onto a spherical object and a dim spot of light appears in the center of the object’s circular shadow. This spot is called a Poisson spot, or Arago spot, and can be explained using the wave interpretation of light.
  • Green or red lasers, diverting lens, optics track and components located in L35, section A. BB in glass slides located in L01, section B6.
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Scattering and Absorption

 

Scattering and Absorption Demo Picture

Scattering and Absorption Demo Picture 2

Scattering and Absorption Demo Picture 3

  • Red laser light penetrates milky solution and is slightly attenuated (top photo).
  • Blue dye absorbs red light but not green light. Red laser attenuation is much greater than green in blue-dye/water solution.

Location

  • Lasers: L35, section A-5.
  • Dye: L35, in cabinet above sink.
  • Beaker: L35, section G-3.

 

 

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Diffraction of light

 

Diffraction of light Demo Picture

  • Shine laser beam through a variety of diffraction patterns
    to demonstrate properties of single and multiple-slit diffraction.
  • Diffraction Accessories located in
    L01, section B5.
  • Calipers located in L35, section D2.

 

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Water Optics

 

Water Optics Demo Picture 2

Water Optics Demo Picture

  • Shine laser beam into a falling stream of water; beam follows
    curve of stream due to total internal reflection.
  • Water Optics container located in L01, section B4. Laser
    in L35 section A5.

 

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Optical Fiber in Oil

 

Optical Fiber in Oil Demo Picture
Optical Fiber in Oil Demo Picture 2

Optical Fiber in Oil Demo Picture 3

Optical Fiver in Oil Demo Picture 4

  • Shine laser through bent optical fiber and total internal reflection is observed. Place optical fiber in tub of oil and laser is no longer internally reflected because index of refraction of oil is similar to that of optical fiber.
  • Oil and optical fiber located in L01, section B5. Red pasco
    laser located in L35, section A5. Ring stand in L35. Clamp in L35, section
    D1.
  • Bring paper towels for clean-up.