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In my spare time I like to make videos on technical subjects, which are published on the Huygens Optics Youtube Channel.

HUYGENS CHRISTMAS SPECIAL: Analog Television Equipment (& Nostalgia) Dec 16th, 2020   
This video is a bit different from my previous videos and not related to optics. I made it purely out of interest for older (analog) equipment and technology. It discusses the principles behind analog TV transmission technology, such as color encoding in composite video signals and RF transmission and modulation methods.

Photons in Radio Waves and Visible Light Oct 30th, 2020   
Experiments with interference of radio waves and visible light. This video shows single-photon interference with 2 slits and 2 paths having different lengths. Unfortunately, i contains a few errors, sorry about this.
1) The explanation in the video at 13:23 was based on speculation without any scientific proof. For a better explanation, please refer to the follow-up of this video, which can be found in the follow-up video: How big is a visible photon?
2) Another flaw in the video is the conclusion about the 2-laser interference experiment (which I confusingly refer to as the 2-photon interference). Basically the average intensities should always add up, regardless whether there is visible interference or not between the 2 lasers. The fact that we don't observe it is caused by the relatively large difference in frequency between the two lasers.

The Real Double Slit Experiment. Oct 5th, 2020   
This video gives a different perspective on a more than 200 years old experiment and discusses in detail both the experiment itself, as well as the quantum mechanics behind it. In the video I show you how you can use a microscope to visualize the wave propagation and the development of the spatial probability distribution for the multi- and single photon experiment.
WARNING: do not attempt to repeat this experiment without using a camera! Looking at laser beams under a microscope with your bare eyes instead of a camera can kill your eyesight instantly and leave you blind for the rest of you life.

Building a Small Cleanroom for Photolithography. Sep 17th, 2020   
This video describes the design- and build process of a small cleanroom space for my workshop. In addition to facilitating working more cleanly, it also allows for working with dangerous substances, such as strong fuming acids, and can be used for processing photoresists. It's build from approx. 5m2 of trespa plate material and uses a HEPA filter and a fan to achieve a steady supply of clean air.

Fourier Optics used for Optical Pattern Recognition Jul 25th, 2020   
Optical Fourier transformations were performed using small lithographic patterns of different characters. A DLP projector can be used as a Fourier filter to do simple pattern recognition.

Light Waves Visualized using Photon Sieves. Jun 29, 2020   
The video shows how the optical wave front of a laser beam can be shaped by means of DIY photon sieves. It also shows how the quality and sharpness of the focal point in a diffraction pattern can be influenced by the number of diffractive apertures in the photon sieve surface.

Making a Mirror with a Variable Surface Shape. Jun 14, 2020   
Video about making a small glass-ceramic mirror with a variable surface shape. Some concepts in this video have been pictured in a somewhat simplified manner to make it more accessible to a less specialized audience.
Making Tiny Fresnel Lenses (in Times of Corona). Apr 5, 2020   
This video shows several types of micro-lenses that I made using a DIY maskless wafer stepper. The tiny lenses can for example be used for building a Shack-Hartmann wavefront detector.

Maskless Wafer Stepper Part 3: Elecronics and Software. Feb 10, 2020   
This is the third (and final) video on the DIY maskless wafer stepper project. It discusses the electronics and software.

Micro Lenses made with Photolithography. Feb 6, 2020   
I'm quite excited to show you the focal properties of the microscopically small lenses that I made using photolithography. These lenses are actually Fresnel zone plates which use diffraction as the method for focussing the light. They were made using the DIY maskless wafer stepper. The lenses have more than one focal plane, and you can easily observe the 1st, 2nd and 3rd order focal planes when they are used in combination with monochromatic light sources.

Maskless Wafer Stepper Part 2: Mechanics Jan 25, 2020   
This video is the 2nd of 3 video's on the design and build process of a small maskless wafer stepper. It discusses the mechanical aspects of the machine, in particular the challenges that I face to achieve the requirements. I also show some crude footage of the first optically active devices.

Maskless Wafer Stepper Part1: Optics Jan 4, 2020   
I've been planning to make a maskless wafer stepper for a long time. In the last few months, I finally found the time! This video is the first of 3 video's on the design- and build process. It discusses the optical aspects of the machine.


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