The future of technology? Photonics shows the way

Clara Zaccaria, Alessio Lugnan and Alessio Baldazzi, three young researchers from the Department of Physics of the University of Trento, have recently obtained funding to develop their projects, respectively from The Kavli Foundation, the Volkswagen Foundation and Rotonium Srl. Their studies are focused on innovative neural interfaces, smart sensing and more efficient and sustainable quantum computing. What do they have in common? These are journeys into light-enabled applications, or photonics.

"This is not the first time that our laboratory has managed to attract important funding from prestigious companies," says Lorenzo Pavesi, head of NanoLab, the Nanoscience Laboratory of the Physics Department of the University of Trento. "This was a happy coincidence because three of our researchers have obtained significant funding from foundations and companies in recent weeks. About 500,000 euros. This demonstrates the quality of their work and is a recognition of the role of physics, and photonics in particular, in responding to the current challenges of scientific and technological development."

Gianluca Lattanzi, director of the Department of Physics, highlights the relationships established over the years with companies, particularly local ones. "The skills provided by physics contribute to product and process innovation," he continues. Those skills will be the focus of the new elective course on "Physics for technological and industrial innovation", organized in collaboration with Confindustria Trento. The classes will be offered to students of the degree programme in Physics in the second semester. The goal is to increase their awareness of the industrial sector as a career option, to inform them about the opportunities of technology transfer and the importance of critical thinking developed through the study of physics for technological innovation in the business sector.

Clara Zaccaria
A nanophotonic chip to read neurons (The Kavli Foundation)

Studying the activity of neurons using integrated optics: to do so, Clara Zaccaria, a research fellow at the University of Trento, has received funding from The Kavli Foundation. The basic idea is to stimulate and monitor cells and circuits of the brain using light emitted by a photonic chip. For this reason, her research aims to design minimally invasive, chip-scale neural interfaces, smaller than 50 microns.
"Current nanophotonic chips,” explains Clara Zaccaria, “make it possible to activate or inhibit neural circuits through optogenetics, with a high temporal and spatial resolution, that is detailed and targeted, and also make their electrical readout possible. Currently, there is no chip-scale photonic platform that can perform optogenetic excitation and optical readout from neuronal networks. The aim is therefore to design and implement the first photonic chip capable of carrying out both these tasks. For the first time, integrated photonic solutions will also be used to collect fluorescent physiological signals from neurons, which are more specific than the electrical readout."
Today there are already optogenetic tools that, by illuminating neurons, enable scientists to investigate what happens in the deepest brain areas, to study the physiological mechanisms and carry out the screening of a series of parameters in different pathological conditions. But in her project, Clara Zaccaria makes one step further.
"The challenge is to miniaturize what is currently done with microscopes and invasive implants, in a photonic chip capable of an all-optical bidirectional communication with neural networks. In addition, the development of biocompatible nanophotonic platforms is extremely important for the creation of reliable and portable platforms for optical manipulation and the monitoring of neuron activity, not only for neuroscience research, but also for technological and clinical applications."

Alessio Lugnan
Smart sensors with brain-inspired hydrogel (Volkswagen Foundation)

Sensor technology is a large and constantly evolving sector that impacts many aspects of life, from medical diagnostics to environmental monitoring. The project “PhotoNeuroGel” by Alessio Lugnan, a research fellow at the University of Trento, who received funding from the Volkswagen Foundation in the framework of the Next - Neuromorphic Computing initiative within a collaboration with Johannes Gutenberg University and the University of Strathclyde, fits into this context.
He proposes to use hydrogel, which is also used for soft and breathable contact lenses, engineered with special molecules that allow it to change shape and colour when subject to light of a certain wavelength. Alessio Lugnan explain the advantages of the technology: "This chemically functionalized hydrogel makes it possible to smartly connect optical, chemical and mechanical inputs. In other words: it makes it possible to combine the processing of images, the detection of chemical compounds (for example in water and in the human body), the perception of vibrations or sound. In a way, it does what our brain does, as it connects and gives meaning to images, smells and sounds."
The hardware is neuromorphic, inspired by the structure and functionality of the brain. While the hydrogel offers advantages in terms of scalability, plasticity and integrability. Photonics provides energy-efficient solutions, while soft matter biochemistry enables optical plasticity by controlling light with light.
"For the first time – he says – the interdisciplinary approach adopted by our team connects three solid lines of research of our respective laboratories in Mainz, Trento and Glasgow. First, we will develop photosensitive hydrogels that can change their physical and chemical properties in a complex and reversible way when subject to light patterns. Next, we will use the millimetre-sized hydrogel unit to implement large-scale optical networks with synaptic plasticity, where local connectivity preserves the memory of past optical inputs. At the same time we will develop photonic devices with enhanced functionality for future neural networks. Finally, we will explore chemical information transfer mechanisms in hydrogels, to understand and exploit their dynamics for future multisensory applications."

Alessio Baldazzi
One or two-photon sources for more efficient and sustainable computers (Rotonium Srl)

There is still a long way to go to achieve efficient and sustainable quantum computers. We need a more in-depth knowledge of photons, the quanta (particles) of light that still have many secrets to reveal.
The research agreement that the Department of Physics of UniTrento signed with Rotonium Srl focuses precisely on this goal. The three-year collaborative project aims to develop innovative quantum circuits and devices made of silicon nitride. The study was coordinated by Alessio Baldazzi, a research fellow at the University of Trento, who explains: "We use silicon nitride because it has very interesting properties for the efficiency of information transport and for the wide spectrum of wavelengths on which it can operate."
Our goal is to study single-photon sources capable of encoding qubits (quantum bits, the unit of quantum information), and to develop an integrated photonic chip that implements quantum algorithms.
"The development of efficient sources of single or paired photons at visible to infrared wavelengths is an enabling technology, which will not only have a significant impact on future commercial and industrial applications of quantum computing, but will also allow the development of numerous other practical applications of quantum photonics," he says.
"We must increase our understanding of the dynamics and the various interactions of the propagation of information. But the real challenge is to create quantum light sources. The sources are essential to create quantum algorithms that can be implemented in integrated systems and photonic processors. In terms of possible applications, we would have more efficient, sustainable and energy-efficient computing. But there are promising prospects for the entire data communication sector."