Lego! It’s a fun toy that is popular around the world. What you may not realize is that it’s also made to incredibly high standards. As it turns out, the humble building blocks are good enough to build a interferometer if you’re so inclined to want one. [Kyra Cole] shows us how it’s done.
The build in question is a Michelson interferometer; [Kyra] was inspired to build it based on earlier work by the myphotonics project. She was able to assemble holders for mirrors and a laser, as well as a mount for a beamsplitter, and then put it all together on a Lego baseboard. While some non-Lego rubber bands were used in some areas, ultimately, adjustment was performed with Lego Technic gears.
Not only was the Lego interferometer able to generate a proper interference pattern, [Kyra] then went one step further. A Raspberry Pi was rigged up with a camera and some code to analyze the interference patterns automatically.
[Kyra] notes that using genuine Lego bricks was key to her success. Their high level of dimensional accuracy made it much easier to achieve her end goal. Sloppily-built knock-off bricks may have made the build much more frustrating to complete.
We don’t feature a ton of interferometer hacks around these parts. However, if you’re a big physics head, you might enjoy our 2021 article on the LIGO observatory. If you’re cooking up your own physics experiments at home, don’t hesitate to drop us a line!
[Thanks to Peter Quinn for the tip!]
I think that’s a neat build and should work fine where changes over time aren’t important. However the plastic used, as most plastics do, has a high coefficient of thermal expansion, which would negate any benefits of precision they had if the temperature changed. I used to make holograms and had a decent homebrew setup. I learned to avoid making plastic parts early on, and making holograms of plastic objects would be difficult as well, with the characteristic banding and areas that would disappear completely that is indicative of movement during exposure.
Perhaps LEGO will consider a line of Invar or zerodur LEGOs?
u wot m8?
Plastic is not metal, it doesn’t expand lol.