Like the XX century has faced the revolution introduced by the advent and the development of electronics, so the XXI century is witnessing the beginning of a new revolution related to photonics.
Photonics is the science and technology that study and exploit the whole electromagnetic spectrum: X-rays, UV, IR, microwaves and the visible light as well. The different features of light can be used to explore the universe, to cure diseases, to solve crimes and also to but also to facilitate everyday life (electronic devices, entertainment, communication...).
Nowadays the lack of imagination is the only limit to the number of discoveries and opportunities Photonics can offer. This exhibition wants to be a journey the discovery of the power of light in changing our lives.
“My eyes saw the Universe in this way 380 000 years after the Big Bang: black,darkness, with a lot of energy/matter and antimatter, clumps of elements rotating incredibly fast. The dark lacerates and the first thermonuclear bombs are primed: the first stars and galaxies. I was born as a photographer but I realized it was impossible to represent my “visions” by photography. I preferred to act on concrete and three-dimensional matter.”
Light carries on a large part of information we use in everyday life through vision, optical fibers and free propagation.
Remote control and TV are a classical example of emitter and receiver. The first one emits IR radiation that contains the instruction for the TV.
The WiiMote works in the opposite way: the bar installed on the TV screen contains two infrared LEDs that can be received by the remote control, so that it can identify position and angle under which the light is received. The information about the position is, then, transmitted to the console using Bluetooth (radio waves).
The laser harp is an electronic musical instrument composed of emitters (lasers or LEDs) associated to receivers (photodiodes) connected to a synthesizer. The interruption of the light beam causes the reproduction of the corresponding note, made by the synthesizer.
Every object having a temperature higher than the absolute zero emits electromagnetic radiation. Through the analysis of this radiation it is possible to obtain information about the temperature of the object.
Thermography is a non-destructive technique to study thermal variations of objects exploiting a particular device called thermographic camera. These objects are able to reveal the light emitted in the far IR (9-14 micron) and create images. Common thermal cameras are able to measure temperatures within -10˚C and 100˚C.
Thermal cameras can be used in maintenance of electrical and mechanical systems, in localization of living beings in environments with no visible light and in clinic diagnostic.
Our eyes are able to “remember” an image on the retina for 1/25s even if the object is no more there to see. If images are reproduced at a rate higher than 25 Hz then we will perceive them as continuous.
A normal smartphone camera records at 30 Hz frequency. This is enough to allow us to perceive the images as a continuum. That’s why we are able to watch videos made with a phone, but we cannot study extremely fast phenomena.
Some cameras are able to acquire images at a much higher frequency (from 100 to some thousands Hz). If the film is, then, slowed down to 60-30 Hz it is possible to study very fast phenomena.
Night vision systems are essential not only for security but also for military and artistic applications. Detection of IR radiation is one of the most common methods to achieve night vision.
There are active or passive detection systems.
The active ones are equipped with an IR projector and collect the reflected radiation through thermal cameras, so that an image of an apparently dark environment can be recorded.
Passive systems are thermal cameras that collect IR radiation emitted by the objects. The resolution of images recorded with active systems is higher than those of passive ones.
Three IR bands are used:
- 810 nm: visible with every night vision systems but they have a residual red halo;
- 860 nm: visible with third generation systems, the red halo is reduced;
- 940 nm: visible with digital systems, no red halo.
Materials behave in different ways when interacting with light: some are transparent, some are opaque and others are fluorescent. The different behaviours depend on the type of material and on the kind of illuminating light.
Under short-wavelength light (blue-purple) illumination, some materials emit fluorescence radiation at a longer wavelength (green, yellow, red). The spectrum of the emitted radiation depends on the material.
We have created different effects with fluorescent materials.
Exhibit realization.Creative process:
- Forced Association;
- Study of Materials;
- Exhibit design
- Hand painting and creation of materials.
- Photoshop and Eat project;
- Printing design and production;
- Colouring in laboratory and hand finishing.
Different kinds of illumination of an artwork lead to different perceptions of the artwork itself. The predominant colours, the three-dimensionality and the perceived details depend on the chosen light. There are no objective criteria to establish the best illumination for an artwork.
The choice of light is the first step of interpretation.
Halogen light produces a warmer sensation respect to LED light, but the last one makes colours brighter, giving new life to artworks.
In collaboration with the "Soprintendenza per i Beni Architettonici e Paesaggistici" of Milan, iGuzzini realized a new lightning for Leonardo da Vinci’s masterpiece “il Cenacolo”.
The LED lights are studied to enhance the chromatic richness of the artwork, improving the control on light distribution and painting conservation, by controlling the room temperature without reducing the overall room illumination.
The new lightning system is provided with seven Palco projectors having a CoB LED source with a continuous spectrum installed on a guide and managed from a control system.
Directional flaps allow to delimit the light beam with precision. The light emitted is warm but it contains a large blue component.
Some materials are opaque in visible light but they become transparent in IR light. This allows us to look through the outward layer of material.
This phenomenon is exploited by IR reflectography, a technique used to study the history and the authenticity of artworks.
In many cases it allows us to observe author’s first-hand paint or to observe the corrections or restorations that were made during the life of the artwork.
Also the layers of filth that deposits on the surface of an artwork are transparent to IR radiation.
Computerized axial tomography (CAT) is a diagnostic method that exploits X-rays absorption from the different tissues of the human body. The thicker the tissue is, the higher will the absorption be.
CAT requires the acquisition of several images (slices) of the same subject, they will be elaborated by a specific software in order to obtain a three-dimensional image.
CAT is used also for archaeological purposes, for example to study the content of a sarcophagus, and for the analysis of artefacts because it allows non-destructive investigations.
Nowadays, lasers have many applications, such as information transmission, data scan, and also surgery and manufacturing. A particular application is laser cutting of several materials, from metal to plastic and from stone to fabric.
The laser cut is extremely accurate and the smallest engravings are provided with an incredibly high quality and precision. Moreover the software control allows to make very elaborated incisions and to make very small holes.
Some typical laser source used for laser cut are:
- CO2 laser (λ = 10.6 micron)
- Fiber laser (λ = 1.064 micron)
- Nd:YAG, Nd:YVO lasers (λ = 1.064 micron)
- Diode lasers (λ = 0.445 micron)
Every interrogation room is divided in two parts separated by a unidirectional mirror, so that detectives can observe the suspect without being seen.
A unidirectional mirror is made of a glass covered with a thin layer of metal that reflects half of the light it receives and transmits the other half.
In order to obtain the desired effect, the suspect’s part of the room must be illuminated with a strong light while the other one should be quite dark.
Looking at the mirror the suspect will see him/herself while the detectives are hidden from the light and can observe the suspect through the glass as if it were a window.
Light has become a very important instrument for investigation on crime scenes. Fluorescence, phosphorescence and chemiluminescence are phenomena that can be exploited to collect evidences.
Fluorescent powders are used to reveal digital prints while some substances, such as saliva, are naturally phosphorescent.
Chemiluminescence, the temporary emission of light through a chemical reaction, is at the basis of the use of Luminol to detect blood stains. Luminol reacts the iron contained in blood and emits light for a few seconds.