Lichtjesavond is the “evening of light” and it is a yearly event that marks the start of the Christmas period. Every December 8th, the main Christmas tree of the city gets lighted up and people have the chance to test some glühwein and buy different handmade products in one of te several stands spread throughout the city center of Delft. This year, we participated with our own stand, with the support from the Optics Research Group of TU Delft, the Science Center and the Photonics4all project, an European Outreach project, funded by the European Commission to promote photonics and light based technologies to young people, entrepreneurs and the general public across the EU.
Our main goal was to promote optics to a general audience and introduce children and families to some experiments hosted at the Science Center and designed by the Optics Research Group. To do so, we came up with three different setups, which showed few basic optical concepts:
- Using the Light Box outreach kit provided by SPIE, we could show what happens when lights propagates through a positive or negative lens, along with the total internal reflection and the diffraction of a grating. Using all the three LED together, we could also obtain white or yellow light.
- In the second experiment, we introduced the idea of polarization. We had a red laser passing through a first linear polarizer na doe could explain that, depending on the rotation of a second linear polarizer, we could block completely the input illumination. Using the same source but interchanging the optical components, we also demonstrate optical absorption by placing blue and red filters within the propagation axis.
- In the last setup, we had different diffractive optical elements, generating complicated figures and symbols, in order to explain the concept of diffraction of light.
Furthermore, we had giveaways consisting of booklets and Fresnel lenses with the logos of our SPIE Student Chapter and the Photonics4all project sticked on them. It has been a very interesting evening with plenty of people visiting us and willing to know more about optics. Children were very enthusiastic they could play with our instruments and see directly the effect of their actions!
We hope to make this a permanent event for our Student Chapter with fancier demonstrations in the coming years!