Tutor: GERACI ANGELO
Advisor: TOSI ALBERTO Major Research topic
:Time-resolved multichannel optoelectronic instrumentation
based on pulsed lasers and single-photon detectors
Thanks to the recent advancements of photonic components and methods in the field of single-photon counting, many different applications are currently growing and some of them will move from scientific laboratories to wider markets in the next future. One of these applications is the time-domain diffuse optics, where brand new instruments and approaches for non-invasively probing biological tissues with scattered light are currently under development. Another example is single-photon LIDAR (Light Detection and Ranging), a technique for non-contact measurement of the 3D profile of a scene by means of pulsed sources and single-photon detectors. In detail, the Time-Correlated Single-Photon Counting (TCSPC) technique enables the reconstruction of faint optical waveforms with picosecond temporal resolution. Time-Domain Near-InfraRed Spectroscopy (TD NIRS) of diffusive media is a technique based on TCSPC that requires two or more laser sources emitting picosecond optical pulses, wide-area single-photon detectors and time-measurement units with picosecond temporal resolution in order to reliably reconstruct optical signals re-emitted by the tissues under test. This measurement technique has been successfully applied in many different fields, such as measurements of cerebral and muscular oxygenation, optical mammography and in-vivo molecular imaging. The primary goal of this PhD research activity is the development of advanced multichannel TCSPC systems that go beyond the state-of-the-art in a few fields, primarily for non-invasive time-domain spectroscopy, thanks to compact pulsed light sources based on laser diodes, single-photon detectors (Single-Photon Avalanche Diodes – Diodes – and the like) and high-performance microelectronic Time-to-Digital Converters (TDCs). In detail, both rack-based multichannel systems for the medical field and battery‑operated ones for on-field measurements will be developed, thus providing advanced instrumentation in the Diffuse Optical Imaging (DOI) research area. Based on the results of this research activity, new solutions for other applications (such as LIDAR) will be developed.