Not only is light useful, cosy and beautiful, it is also terrifically interesting and full of unexpected applications!
But that is something we will let the visitors to the Ghent Light Festival 2018 discover for themselves in the foyer of the Universiteitsforum Building (Ufo).
Smack in the middle of all the spectacular light artworks, dozens of enthusiastic light researchers from Ghent University will amaze you with interactive demos.
Some of the demos are part of the interactive exhibition ’Zonder licht wordt het donker! - Without light, it’s dark!’ For students in their last two years of secondary school, these demos can also be visited with a guide during the week following the festival.
Light and life
How do you correctly diagnose diabetes if the traditional method using blood sample analysis is not possible? That is a question that doctors in developing countries are asking themselves with increasing frequency. The incidence of diabetes is increasing, but blood tests are expensive and time-consuming. Ghent University researchers have found a solution using infrared spectroscopy of the fingernail. By analysing the way in which infrared light reflects off a person’s fingernail, doctors can gain insight into the molecular structure (in this case, the saccharification or ’sugarification’) of the fingernail. This turns out to be a reliable method for distinguishing diabetics from non-diabetics. Curious’ Come and get tested during the Light Festival!
To capture light energy for photosynthesis, plants and algae have specially adapted molecules. These molecules are called pigments. Each type of pigment captures light at a specific wavelength (’colour’) of the visible light spectrum. The light that is not captured is reflected and gives the pigments (and the plants and algae which contain them) their typical colours. That is why some plants and algae are more red or brown than green. Microalgae and their pigments are used by humans in numerous applications, for example, in the food industry, in aquaculture, in biotechnology and in cosmetics. The pigments in microalgae can even be detected by satellites, and scientists make clever use of this fact for monitoring, from space, the annual bloom of microalgae throughout the world.
You have probably already noticed it yourself--the plants on the windowsill grow enthusiastically in the direction of the window (and the light, of course). If you want them to remain upright, you have no choice but to turn them once in a while. But why do plants do this’ And how do they see where the light is’ They don’t have eyes, do they? Do they see the difference between red, blue and white light? Bring out your (and your children’s) inner scientist, and discover the answers here!
A large part of the body of a plant lives in the dark and never sees the light of day. This is why roots are sometimes called the hidden half and why they have also long been ’underexposed’ by scientists. The Root Development Group (Ghent University/VIB - Flemish Institute for Biotechnology) is changing all that. By using genetic modification to couple luminous (light-emitting) proteins to interesting root proteins, the researchers can literally see precisely what is happening in the living, growing root! To do this, they use a fluorescent protein extracted from jellyfish, although the protein which causes the bioluminescence that make fireflies shine so brightly in the dark is also sometimes used. This group has also converted an existing microscope into one through which you can view growing roots without having to lay them flat under the microscope.
Get creative, give yourself a workout, and make some music with the laser harp. You ’play’ this harp by stroking a series of laser beams, interrupting the paths of the beams. This exhibit is an example of how signals, just like in a scientific experiment, can be detected and processed, in this case, into music. In this demo, light detectors detect when the laser beams are interrupted, and this signal is then processed by an Arduino microcontroller. This microcontroller then transmits a MIDI signal which is converted to sound by a (software) synthesizer. Play on!
Make your own light painting here at the Festival and become one of the Light Festival Artists! In front of a camera, you wave a series of light-emitting materials in various colours through the air, and we immediately project the results onto a large screen. Abstract or less abstract--follow your instincts!
In this game, you use your own shadow to interact with a virtual object, in this case a bouncing ball. The ball is projected onto a screen with a bright background, and a camera registers the shadow you create by placing your hand in front of the projector. A computer algorithm then determines how the ball moves in response to your shadow hand.
NB-Photonics Village--Light in all its forms, dimensions and applications
The Internet superhighway does not work with electrical zeros and ones but with short pulses of light, which zip along thin, glass fibres. And because light is made up of different colours, you can have many signals running through one fibre simultaneously. In an interactive demonstration, we show you this light conduction in glass fibres and how various beams of light of varying colours can be combined. The light from two lasers, each of a different colour, is combined into one bundle, which is transmitted over several metres of glass fibre. At the other end of the fibre, the intensity of the light is detected and converted into an electrical signal which is shown on a PC screen.
Would you like to know if your blood is carrying sufficient oxygen to your muscles’ Then, measure the colour spectrum of your blood. This is just one of thousands of applications of light spectroscopy. Light spectroscopy is used to measure the spectrum of light that has undergone an interaction (absorption or diffusion) with a material. This interaction is different for every material, and therefore the spectrum - or how much light of each wavelength or colour is absorbed - ’reveals’ the composition of the material. In this demo, we show you how a spectrometer works, and you can take a look at the spectra of all kinds of materials. You will also see that the mechanical vibrations of molecules are an important cause of the peaks in the spectra. And, of course, you will also be able to measure if the oxygen saturation of your blood is up to par.
In most circumstances, light behaves rather indifferently. If you turn on a second (identical) lamp in a room, you double the amount of light. What’s more, light particles do not usually interact with one another: Bringing together a blue and a yellow photon does not produce two green photons. This is light as we know it. But, in certain materials or under special circumstances, usually when there are very many light particles present, light behaves in extraordinary ways. Find out how a green laser works and how we can tinker with the wavelength (or colour) of light to make invisible light visible.
The computer chip in your laptop or telephone performs millions of computations per second by transmitting, controlling and receiving short signals in electrical circuits. There are many advantages associated with receiving these electrical pulses through light pulses, although to do so, the architecture of computer chips will have to be radically redesigned. Discover the basic principles of this type of light-controlled chip or "photonic integrated circuit (PIC)". You control "switches" to direct the various functions connected to the circuit and can immediately see the effects of your actions on the flow of the light.
Nowadays we are spoiled with high-quality, super-small cameras - for example, the camera in your smartphone - but cameras existed centuries ago and were used to "photograph" landscapes, among other things. Yet, to do this back then, you had to have a large, dark chamber (a camera obscura) with a small hole in one side. This hole allowed an image to appear on the opposing wall of the camera obscura. But what does this image look like now? Well, we have built one of these camera obscuras so you can come and take a look!
There are more varieties of photons, or light particles, than there are colours of the rainbow. Infrared photons have a somewhat lower energy than visible light and can be used, for example, to measure temperature remotely. Of course, every ’object’ radiates photons at a certain temperature (you do, too!), just like a glowing ember of wood. In our photo booth, you can take a double photo of yourself - a #selfIR - this photo consists of a ’regular’ image and, at the same time, an infrared image. What’s more, we will show you all the things you can do with an infrared camera and how you can use one to check whether your roof is well insulated.
The incandescent lamp served us well for over a century, without hardly any alterations to its design in all that time. But the end is now clearly in sight. Energy-saving bulbs - which turned out to be nothing more than a transitional technology - are passing the torch to the LEDs (light-emitting diodes). In these interactive demos, you will learn how these three technologies compare in the areas of efficiency and colour quality. Of course, lamps not only have to emit white light, they must also render the colours of objects realistically. And the fact that this is not as easy as it seems is something you can discover for yourself in this interactive exhibit. Luckily, microscopic particles and exotic chemical elements, such as cerium and europium, are there to help you with this.
Since the invention of the first microscopes at the beginning of the 17th century, the study of living tissues and cells has fascinated many researchers. Here, we will exhibit a new optical technology which is not only capable of viewing cells but can also transport large molecules into cells with the help of light and nanotechnology. When light is shone on them, minuscule gold particles can generate temporary passageways through the cell wall, allowing molecules to pass into the body of the cell. The possibilities of this technology are illustrated using light-emitting molecules which are introduced into specific cells, where together they make a living painting.
Solar panels generate electrical energy from sunlight. If we want to use these panels to supply all of our energy needs, then at night there will be a shortage of energy, and when the sun is shining brightly, there will be an excess. Luckily, this isn’t happening simultaneously all over the world. In the ideal scenario, we could transport the excess energy with minimal loss to other locations where there is a shortage. Come and, with the help of rotating solar panels at various locations and with various orientations, test out how much energy production is anticipated at each moment. Optimise the cooperation between these solar panels, and try to ensure that everyone gets the energy they need throughout the entire year.
Radar technology was originally developed for military purposes. A transmitter sends out short pulses of radio waves, and when they collide with a plane or boat, some of these waves turn back. This allows you to determine the distance and the speed of the reflecting object. The "storm radar" of today works in precisely the same way but by measuring the reflection off rain showers. At the Festival, we will demonstrate the LIDAR version, in which pulses of light are transmitted instead of radio waves. Using our LIDAR, we make a three-dimensional scan of your body - from a distance - and it appears immediately on a screen, just like the rain showers.
How do we see the world in 3D? How does a 3D television work? Why are there so many different types of glasses, and do you always need to have a pair? And why do some people get sick when they watch a 3D film in the cinema? At this exhibit, you will learn about the basic principles of different types of 3D displays.
Modern TVs can produce sparkling colours and razor-sharp images, but they are still relatively limited when it comes to light intensity. HDR television (high dynamic range TV) is changing all that. Thanks to these TVs of the future, which can radiate more light and render deeper blacks, images are really life-like. Come and view the special demonstration film from the VRT (Flemish Radio and Television Broadcasting Service) on our HDR prototype, and discover the special software developed by Ghent University to allow the viewing - and even the capitalisation! - of traditional films using this new technology.
Come meet the synchrotron! The synchrotron is a circular particle accelerator, with a circumference of several hundred metres up to several kilometres, that generates super powerful X-rays. X-rays are a type of light radiation which is invisible, like UV light, but which is many times more powerful than UV light. Researchers at UGent use synchrotrons, like those in Grenoble, as super telescopes. The X-rays can penetrate deep into objects while at the same time generating images of the object’s matter on a very, very small, atomic scale. We show how these synchrotrons work and what kinds of research we can perform with them.
IceCube is one of the largest scientific installations in the world. Buried in one cubic kilometre of ultra-clear ice, two kilometres deep under the surface of the snow at the South Pole, IceCube contains more than 5000 light sensors. These sensors detect neutrinos from the so-called ’cosmic radiation’. These neutrinos arrive on Earth with enormous quantities of energy from the cosmos. Neutrinos fly right through the Earth, but very occasionally they ’collide’ with one of the particles present here. When that happens a small flash of light is generated, which the sensors can detect. At the Festival, we are exhibiting a 1/500 scale model of the IceCube telescope, which shows how we can detect these cosmic particles and how we can then discover something about the place where these particles were formed.