Portrait of Edoardo Charbon
Professor Edoardo Charbon
Native of Collina d’Oro, near Lugano
Lives in Jouxtens-Mézery (VD)
Born in 1964
Director of AQUA laboratory, EPFL Neuchâtel
Edoardo left his home canton of Ticino for Zurich, where he graduated with a bachelor’s degree from ETH Zurich. He then crossed the Atlantic and obtained his master’s degree at U.C. San Diego, then his PhD at U.C. Berkeley. On his return Europe, he taught at two universities: from 2008 to 2016 as full professor in Delft, where he first worked on quantum technologies; at the EPFL from 2002, where he was assistant lecturer and lecturer before being appointed full professor in 2015.
He currently heads the AQUA (Advanced Quantum Architecture) laboratory, located in the building of the Neuchâtel branch of the EPFL. He is backed up by a team of thirty employees and appreciates the team’s multicultural character and collaborative spirit. His management style is results-oriented, with efficiency counting for more than time spent in the laboratory.
We talk to a scientist whose research results are an integral part of the objects we use every day.
What are the important principles governing quantum physics?
Quantum physics emerged in the 20th century and made it possible to describe certain types of non-trivial behaviour of atoms and particles, which the physics of the 19th century had not been able to explain. Based on one of Planck’s ideas, Einstein hypothesised that light waves are also made up of corpuscles, or photons. The first important principle to understand is that of superposition of states. A photon, an electron or even an atom can be in different energy states at the same time. From this first principle follows the second principle, that of entanglement: constituents (atoms, for example) of systems that have interacted in a certain way remain connected, which makes it possible to cause the states of the two systems to change at the same time. These are principles that are used in quantum computing and other fields of science and engineering.
What is the main technology that you use in your research?
CMOS technology – complementary metal oxide semiconductor – is a manufacturing technology for electronic components. It is used in all microchip applications: computers, telephones, electronic devices, etc., and has been constantly evolving since its inception in the 1960s.
CMOS technology is used in an integrated circuit, also known as an electronic chip. This circuit consists of an electronic component, based on a semi-conductor that reproduces one or more electronic functions of varying complexity, often with several types of electronic component built into a small volume. The transistor is one of these electronic components, which functions like a switch. If several transistors are connected together, the behaviour of the overall assembly depends on the state of each transistor, blocking a current or letting it pass.
How do you use CMOS technology in your projects?
We have utilised this technology to produce detectors of a type known as SPAD – single photon avalanche diode – measuring just a few micrometres in width. They enable the detection, counting and timing of single photons, natural or artificial, in the environment. A miniature camera comprising millions of SPAD pixels can measure distances ranging from a few centimetres to several kilometres. This technology has been incorporated into dozens of brands of mobile phones. For example, a detector is fitted behind the glass of the telephone, in order to see whether a person is in front of the screen or not and thus determine whether the screen should be lit up or not. This has enabled a significant increase in battery service-life. In 2018, 1 billion of these detectors were sold.
In the medical field, another technology, also based on the SPAD, has made it possible to obtain a much more precise vision of tumours, for example. Thus, when a PET (positron emission tomography) scan is carried out to locate a tumour, the contrast agent injected binds itself to the cancerous cells. The molecules of this product emit positrons, which, when they meet electrons, emit energy in the form of gamma rays. These gamma rays are detected by the SPAD by scintillation and a computer reconstructs the image of the tumour in 3D. This allows very precise visualisation and elimination of the tumour with the least possible impact on the body.
To learn more about the CMOS-SPADs technology, visit the AQUA lab webpage.