Application of advanced spectrometer in geometrical optics?

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Discussion Overview

The discussion revolves around the application of an advanced spectrometer in experiments related to geometrical optics. Participants explore potential experiments suitable for freshmen, focusing on the intersection of spectrometry and geometrical optics concepts.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • One participant suggests examining the spectrum of a propane or butane flame, highlighting the emission from electronically excited C2 and the quantization of vibration in the spectrum.
  • Another participant proposes measuring the spectra of discharge lamps, specifically comparing hydrogen and deuterium lamps, contingent on access to appropriate power supplies.
  • A participant expresses a desire for experiments specifically in geometrical optics for freshmen, noting the relevance of wave optics applications.
  • One suggestion involves measuring refractive indices of materials using Snell's Law, with an emphasis on using laser pointers to observe dispersion curves.
  • Another participant questions the appropriateness of using a spectrometer in a geometrical optics lab, arguing that geometrical optics is wavelength independent and suggesting that chromatic aberrations may complicate the use of the instrument.
  • A later reply recommends using the minimum deviation angle of a prism as an alternative method to measure refractive indices, emphasizing the observation of spectrum lines through a telescope.

Areas of Agreement / Disagreement

Participants express differing views on the suitability of the spectrometer for geometrical optics experiments. While some suggest specific experiments, others challenge the relevance of the spectrometer in this context, indicating a lack of consensus.

Contextual Notes

Participants note that geometrical optics is generally considered wavelength independent, raising questions about the applicability of spectrometry in this field. There are also discussions about the limitations of using certain methods and the need for appropriate equipment.

Dorea
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We have an advanced spectrometer in our geometrical optics lab! I'm seeking for any experiment in geometrical optics to include it!
 
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Dorea said:
We have an advanced spectrometer in our geometrical optics lab! I'm seeking for any experiment in geometrical optics to include it!
This spectrometer is useful for looking at atomic and molecular spectra. A very nice experiment would be to examine the spectrum of a propane or butane flame. The blue color of the flame is primarily due to emission from electronically excited C2. The major structure in the spectrum is due to the quantization of vibration in the excited and ground electronic states. c.f. http://en.wikipedia.org/wiki/Swan_band

You can also measure the spectra of discharge lamps. It is interesting to look at the difference between hydrogen and deuterium lamps -- assuming that you can get access to a discharge lamp power supply with H and D lamps. Google "spectrum tube power supply" and "spectrum tube" to see where to buy these/what these look like. The power supply is ca. $100, the tubes are ca. $20/ea.
 
Thank you for answer.
There's many application for it in wave optics. More, I'm asking for experiment in geometrical optics field for freshmen!
 
Dorea said:
Thank you for answer.
There's many application for it in wave optics. More, I'm asking for experiment in geometrical optics field for freshmen!

I see. The only thing that I can think of is to do some work measuring refractive indices of materials (Snell's Law). With a small set of laser pointers, you could measure the change in refractive index as a function of wavelength (dispersion curves) for some simple solid materials. If you have a "water prism" you could also measure this for some pure liquids.
 
Dorea said:
We have an advanced spectrometer in our geometrical optics lab! I'm seeking for any experiment in geometrical optics to include it!

Strictly speaking, I don't see how this is possible- geometrical optics is wavelength independent, and chromatic aberrations are likely beyond what you are thinking.

I suppose you could do some version of Snell's law, Fresnel reflection/transmission coefficients, etc if you have a monochromatic light source. Maybe something with double refraction (uniaxial crystal optics). But all of these are ad-hoc excuses for using the instrument, as opposed to actually learning something.

Why did you guys decide to use this for a geometrical optics lab, as opposed to a wave optics lab?
 
Quantum Defect said:
measuring refractive indices of materials (Snell's Law)

Instead of using Snell's Law directly, try using the minimum deviation angle of a prism. While watching a spectrum line through the viewing telescope, rotate the prism. You should be able to see the line move back and forth across your field of view, and locate the extreme angle in one direction.
 

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