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BUILD A LASER INTERFEROMETER:Any day now, scientists are expected to declare they have detected gravitational waves (via LIGO). This discovery will support a prediction made with Albert Einstein's general theory of relativity. It will also add to our understanding of the universe.
Here I present a paper first published by the Newport Corporation on making your own laser interferometer. While not as precise as the massive instruments utilized by the scientists for gravitational waves, this tabletop method WILL allow you to detect very minute changes (within wavelengths of light) being made by thermal and vibrational changes in the environment. It is a DIY project, and if you already have the materials in your school science lab, you can begin right away. Just follow the layout and instructions.
I present this page and PDF paper to you so that you will know that Laser Interferometry is within the reach of amateurs, hobbyists and students / educators. You may wish to obtain further instruction via the web to enhance your project, including instructions on making holograms if you do not already have any experience, in case you wish to experiment with holographic interferometry: non-destructive testing. But, don't worry, laser holograms are easy to make!
Once set-up is complete, if any components in the setup move unexpectedly, even very slight movement, this changes the optical path from one component to another, therefore altering the optical effects. You can illustrate this by touching the back of one of the mirror mounts, which will flex it forward slightly, thereby shortening the optical path to the mirror. Notice how this causes fringes to move acorss the blown-up output display, moving one fringe to the next for each half-wavelength.
This project description is saved as a 400k PDF file: DOWNLOAD HERE. You can use the photo at the top of this page to note the arrangements of the optical components (basic laser, mirrors, beamsplitter, objective lens, and white card in a holder).