The Fabry-Perot Interferometer: What Do the Fringes Mean?
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- Опубликовано: 30 сен 2024
- So, you are doing your pre-lab due diligence for a Fabry-Perot experiment. You're not alone if you don't see a straight line between the descriptive mathematics and the fringes. I did some soft experiments to help me to recognize the meaning of the fringes. There are a lot of variables to control in a real experiment and running simulations can be so helpful because you can know and control the extraneous factors. That's what's going on in this video. Enjoy!
Typo at 7:00 - There should be a factor of t-squared multiplying the ratio of cosines. At 7:20 the next line appears correctly with a factor of t-squared multiplying each cosine ratio.
The simulations described in this video were done using Zemax OpticStudio (www.zemax.com).
As a bonus, at the end I give a "hand-wave-free" explanation of why it is okay to ignore the phase shift the light experiences upon reflection.
If you really don't need the theoretical background of the Fabry-Perot interferometer (Part 1), you can skip ahead to 9:14 (Part 2) where the soft experimentation using MATLAB and Zemax begins.
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References
1. B.E.A Saleh and M.C. Teich, Fundamentals of Photonics; Part I: Optics, 3rd ed. (Wiley, 2019), Section 11.1
2. Pedrotti, Pedrotti, and Pedrotti, Introduction to Optics, 3rd ed. (Prentice-Hall, 2007), Section 8-4
3. Eugene Hecht, Optics, 4th ed. (Addison Wesley, 2002), Section 9.6.1
Typo at 7:00 - There should be a factor of t-squared multiplying the ratio of cosines. At 7:20 the next line appears correctly with a factor of t-squared multiplying each cosine ratio.
Really useful video, thankyou!
just noticed at 8:28 the double angle formula given is wrong, should be cos (2 delta) = 1 - 2 sin^2 (delta)
@josephbennett82 Thanks for noticing. Fortunately it's just a typo on the slide and not some horrible propagating mistake. The form of the double angle formula that I meant to show there is cos(delta)=1-2sin^2(delta/2). The "1-" was left out.
Wow, I'm an EE major in an optics class and the textbook and slides got so gnarly around this topic and you just breezed through with great visuals and explanations for everything covered in class. Thank you so much for demystifying the Fabry-Perot interferometer, this video is incredible!
Thank you for making this video!
Does Zemax take into account the coherence of light, and full wave nature of light?
Thank you so much for the video. I was wondering if there are any books you can recommend on this subject? Thanks in advance. I really appreciate your work.
Yes, and I think it would be really great if other viewers could chime in here with their own recommendations. I got a lot out of the treatment in Saleh and Teich, and also from Pedrotti, Pedrotti, and Pedrotti. But there was also plenty that I learned from experimentation, and I admit I have lost track of specifically what I have learned from reading and what I learned from experimentation. And when I say experimentation I am referring to both hard and soft experiments (hardware and software), but mostly soft experiment for me on this topic. And actually it's the soft experiments where you learn a lot and learn it quickly because it's versatile and quick, and you can immediately understand your results. For me there was the use of MatLab and also the use of nonsequential ray tracing, both of which I demoed a little bit in the video. But of course you're right in hitting the books first to get the foundational knowledge that you can then knowledgeably use in those experiments.
Best explanation I've seen on Interference fringes. But I still cant follow why we see the fringes at all. I understand the idea of constructive and destructive waves, but the waves of light are moving at c, but the fringes are static. Have you created a standing wave of light here? This must be the answer. If so, then the light is now not moving at c anymore, its a stationary wave in a confining resonant cavity, between the mirrors. So then what can still be moving at c?
Good afternoon. This question may have been raised somewhere, so I apologize. The bottom line is that there is a Fabry-Perot interferometer and how to adjust the parallelism of these mirrors is not entirely clear, so far I have found that by interference rings in diameter, if the reception goes to the camera, then shine with a precision LED. Thanks in advance for your advice.
Sir, then why other wavelengths get die out. Why there is only one wavelength coming out of the FP etalon?
Sorry for the delayed response. I will be lazy and refer you to a video about tuning diode laser resonators. ruclips.net/video/FjzHvWFrlZo/видео.html