BANDO PRIN 2022D. D. N. 104 DEL 2 FEBBRAIO 2022

TITOLO DEL PROGETTO: MId infRAred laBel free Interferometric detectorLess Imaging in photonic circuitS - MIRABILIS 

CODICE CUP: D53D23002780006

Budget: € 74.871

P.I. o Responsabile U.R. : Massimo Brambilla (P.I.)

Altre Unità di Ricerca o eventuali Sub Unità: PoliTo, UniBa

Breve descrizione del progetto
The project MIRABILIS is meant to combine three key features in optical imaging within biologically relevant spectral windows of the radiation (mid-infrared): a) the implementation of Single Pixel Imaging (SPI) of a target, using an illumination provided by a speckle field pattern, generated either in free space or in a photonic platform; b) the use of Optical Feedback Interferometry (OFI) in a diode laser or in a Quantum Cascade Laser (QCL) to gather target properties provided in the sPI scheme described above, without making use of an external detector; c) characterize and classify target features using machine-learning algorithms. 

Finalità
The project MIRABILIS is formulated to achieve phantom tissue imaging in the Mid-Infrared, based on Optical Feedback Interferometry (OFI) in a Quantum Cascade Laser (QCL) and Single Pixel Imaging (SPI), using an illumination provided by a speckle field pattern. The validation was to be provide both in free space and in a photonic platform (Optical Phase Array, OPA) 

Risultati attesi
The three main expected results and innovative elements of the project are: a) the use of a Photonic Integrated Circuit (PIC) such as an OPA to provide controlled, multiple, illumination patterns of a target, encompassing a programmable stage to comply with the following item; b) the collection of reflected light patterns from the target and their reduction to a one-dimensional signal to be treated with Single-Pixel Imaging (SPI) techniques, with the additional contribution of Machine Learning (ML) based algorithms; c) the discrimination and processing of such SPI signal by the master laser itself in a
Self-Mixing-Interferometry scheme, which leads to reconstruct target information from the voltage measurements at the laser contacts

Risultati raggiunti
MIRABILIS assessed the possibility of exploiting Compressed Sensing (CS) / SPI imaging methods either using an external detector or, most relevant, in a configuration of OFI scheme. where the laser providing target illumination also detects the feedback by measuring the voltage variations at the laser contacts. The image discrimination and classification was pursued by means of state-of-the-art ML techniques. In parallel image reconstruction was obtained 

based on speckle illumination and single-pixel signal collection. All the above goals were complemented by innovative modelling and simulations in prediction, support and steering thereof.
The second achievement of the project is the design and validation of OPA in the mid-infrared, opening the road to silicon-platform-based imaging with photonic devices. In the MIR spectral region, the design of a reliable PDKs (Process Design Kit) required the novel design and simulations of all the necessary elements via commercial and self-developed tools. 

In the near-infrared spectral range, a prototype of a short range OPA operating at 1500 nm was obtained via a collaboration with ST-Microelectronics and allowed for the first proof-of-principle of
OFI imaging with a double passage through a complex PIC.