Experimental Optical Interferometry (Physics 445/545E) is a 5-week, 1-credit physics laboratory course that covers basic experiments in interferometry, interference spectroscopy, thin films, lasers, cavities, convolutions and spectral line shapes. This 3-hour lab will meet once a week for five weeks during which time students will hear lectures, see demonstrations, use laboratory instrumentsand build a Fabry-Perot interferometer that can be pressure-scanned, piezo-scanned and q-scanned.

Theory deals with the interferometer and associated optics/electronics that make it useful as a Fourier spectrometer. The transmission and reflective intensity distributions will be derived and related to the convolutions needed to measure the widths, shifts and shapes of spectral lines.

Experiments deal with the set up of the three scanning interferometers, their alignment and operation. The Fabry-Perot will be interfaced with a grating spectrograph and narrow band interference filters to get data from the widths and shapes of spectral lines. Data will be computer analyzed to get the temperature, magnetic field and electron density of a helium plasma.

Here's what you will do in this laboratory:

1. Set up and align three Fabry-Perot interferometers
2. Observe and photograph the fringe system for various optical parameters
3. Analyze the signals to learn about the Fabry-Perot or the source.
4. Set up a pressure-scanned Fabry-Perot and associated optics
5. Pressure-scan to get data about the Dl - the wavelength separation of two spectral lines
6. Set up a piezo-scanned Fabry-Perot
7. Piezo-scan to get fast changes of the line shape and shift and time dependent source properties
8. Set up a theta-scanned Fabry-Perot
9. Measure the fringe pattern to determine the plate spacing and spectral range
10. Analyze all data and determine the quality of the Fabry-Perot, optics, source and signals
11. Compare the Fabry-Perot with grating, prism and filter spectrometers
12. Measure Fabry-Perot plate reflectance from the time decay of the intensity and/or fringe sharpness

1. How to setup, align, calibrate a Fabry-Perot interferometer
2. How to use the Fabry-Perot to do high resolution spectroscopy
3. The theory of the Fabry-Perot etalons, ml = 2nd cos q and the Airy intensity pattern
4. How to set up input and output optics to convert the Fabry-Perot into a measuring instrument
5. How to get information from the Fabry-Perot fringes recorded with a PM, CCD or photographic plate
6. How to use the Fabry-Perot to measure the shapes and shifts of spectral lines
7. How to measure temperature, doublet separation, Zeeman and Stark effects
8. How to measure fast time-dependent plasma properties
9. How to cross a Fabry-Perot with a spectrograph to form Fabry-Perot images on spectral lines
10. How to create a Channeled Spectrum (Edser-Butler bands)
11. Similarities of the Fabry-Perot, Michelson and Mach-Zehnder interferometers
12. The basics of interferometers, thin films, interference filters and interference spectroscopy.

This course is intended to serve students in physics and other disciplines who will not normally take the Physics Advanced Laboratory (Physics 480/481a,b), Optics (Physics 320), or Atomic Spectroscopy for Experimentalists (Physics 474/574). The topics covered in this experimental course will be especially useful tostudents in Astronomy, Optical Sciences, Electrical Engineering, Physics and AAtmospheric Sciences

Other experimental physics laboratory courses in this sequence are:

• Physics 445/545A Experimental Spectroscopy
• Physics 445/545B Experimental Acoustics
• Physics 445/545C Experimental Microscopy, Light Scattering and Optics of Small Particles
• Physics 445/545D Experimental Geometrical and Physical Optics
• Physics 445/545E Experimental Optical Interferometry
• Physics 445/545F Experimental High Vacuum Techniques and the Thermodynamicsof Gaseous Systems

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