Laser Interferometer - Part 1: The Optical Design.

⚡Introduction to the design and optical layout of an open source laser interferometer for measruing lengths in the nanometer regime over large distances of up to 1 meter.

The project aims to be accessible avoiding costly components and complex machined parts.

(Note: There is a small error in the picture of the 'Michelson Interferometer with Offset' - the detector is drawn on the wrong side.)

CHAPTERS:

00:00 Introduction
01:20 Design goals
02:02 Light source
05:14 Interferometer topology
06:35 Corner cube reflector demo
08:13 Chosen optical layout
11:04 Blender beam path animation
12:15 Live demo & Interference signal
14:20 Laser beams & Outro

RECOMMENDED RECOURCES:

* Optical Interferometry Part 1: Introduction & ZYGO GPI layout
(Detailed introduction to interferometers by Huygens Optics)

* Light & Coherence part 1: Temporal Coherence
(Great explaination of coherence length by Huygens Optics)

* Free Optics Simulation in Blender - Tutorial
(Simulate your own optical systems)

* MIT Video Demonstrations in Lasers and Optics
(Old but highly recommended)

* SAMS Laser FAQ - Laser Instruments and Applications:
(One of the most comprehensive collection of information on Lasers)

* Mode Stability of Diode Lasers
(Very detailed analysis of different laser diodes for holography)

[rodfrey]

Outstanding. Don't shy away from the information density, I suspect anyone interested in 100nm precision is here to geek out on the details.

[merijnotterman]

Amazing project, would love to build it when you're finished.

One tip you might find useful for your reference arms: You likely want a very low CTE material. Invar or zerodur is likely way too expensive, but there is a trick you can do with two different cte materials.

Example: Say you want a distance of 25mm between point a and b. Take a piece of 50mm steel, point a is on one end, now attach a piece of 25mm aluminium to the other end facing towards point a. At the end of this aluminium piece is point B. So a and b are now 25mm apart. Due to the CTE of aluminium being twice that of steel, and the steel part being twice as long, they expand by the same amount and thus the distance between a and b doesnt change.

Without a drawing its a little difficult to explain so I hope its clear. If not let me know.

[cylosgarage]

Really awesome stuff. The frequency stabilization idea is awesome. Looking forward to the next part.

[HuygensOptics]

Very nice video and content, I really enjoyed watching this. Thanks for all the effort that you put in!

[Rob_]

I have been thinking about a laser interferometer some time ago and even discussed this with some people better knowledgeable in this topic and they all quickly told me that I cannot do this with common "hobby grade" stuff.
It looks like I just need a bit more advanced "hobby grade stuff" but I also realize this will give me a lot of sleepless nights re-running the theoretical stuff in my head. So I subscribed, hoping for lots of those sleepless nights 😁

[RandomToaster]

Liking and engaging in the hopes the algorithm continues to bless you.

[Leo.Wolf.the.Engineer]

The wavelength stabilizing bit is a great idea! Im very curious to see where this goes!

[digitalRight]

Excellent work, thank you for contributing to the accessibility of precision technology

[HansRosenberg]

Fantastic content! I'm an electronics engineer myself, but I love optics! Very good video quality and presentations. Good job!

[thomas]

I'm really looking forward to the upcoming videos! The design is fantastic and would make an excellent project for my CNC—first for milling and later for geometrical compensation of my machine and Heidenhain scales. Greetings from Germany!

[squelchstuff]

Brilliant!
Oh wait, pun unintended, but I'll roll with it. I'm certainly looking forward to how this unfolds.

[grottyboots]

Excellent video! I used Renishaw interferometer equipment in a previous career (CNC machine setup & calibration). They gave us some basics of how an interferometer works, but you're taking it another level. Moar!

[zakqwy]

Ah what an exciting project! Can't wait to follow along, thanks for posting.

[Kaliumcyanidful]

Just wow! I wanted to own/built in interferometer, but it just wasnt in reach. Thank you a lot for posting! 😊

[GermanMythbuster]

Very cool, great job!
Can't wait to see part 2 ❤

[KacperPotoczny]

Great stuff! Can't wait for more. For me, information density is just spot on

[EbisLab]

Awesome design! Thanks for publishing this

[wintchx]

great video and channel! amazing explanation and proyect, i will keep an eye on this!

[gr]

Great video! I'm delighted you used my image from wikipedia which is licensed for free use but if you had clicked on the image you would have gotten a much higher resolution image to use in your video. I love the combination of diagrams (and in 3D!), video of actual parts, and easy to understand narration.

[nielsdg]

Great video! I love the link with the practical setup! Last year I built a homodyne displacement interferometer myself with LEGO, aliexpress and 3D printed parts, where I had to deal with exactly the same issues as highlighted by you. Let me know if you're interested in my summary document. Looking forward to the future parts of this series!