Giovanni Finco


Last Name

Finco

First Name

Giovanni

ORCID

0000-0002-1218-1924

Organisational unit

09531 - Grange, Rachel / Grange, Rachel

Filters

2022 - 202529
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Publications 1 - 10 of 29
  • On-chip Time-Bin Entangled Quantum State Generation and Tomography for Optical Quantum Communication
    Item type: Other Conference Item
    Finco, Giovanni; Chapman, Robert; Grange, Rachel; et al. (2024)
  • Monolithic thin-film lithium niobate broadband spectrometer with one nanometre resolution
    Item type: Journal Article
    Finco, Giovanni; Li, Gaoyuan; Pohl, David; et al. (2024)
    Nature Communications
    Miniaturised optical spectrometers are attractive due to their small footprint, low weight, robustness and stability even in harsh environments such as space or industrial facilities. We report on a stationary-wave integrated Fourier-transform spectrometer featuring a measured optical bandwidth of 325 nm and a theoretical spectral resolution of 1.2 nm. We fabricate and test on lithium niobate-on-insulator to take full advantage of the platform, namely electro-optic modulation, broad transparency range and the low optical loss achieved thanks to matured fabrication techniques. We use the electro-optic effect and develop innovative layouts to overcome the undersampling limitations and improve the spectral resolution, thus providing a framework to enhance the performance of all devices sharing the same working principle. With our work, we add another important element to the portfolio of integrated lithium-niobate optical devices as our spectrometer can be combined with multiple other building blocks to realise functional, monolithic and compact photonic integrated circuits.
  • Pedestal High-Contrast Gratings for Biosensing
    Item type: Journal Article
    Beliaev, Leonid Yu.; Stounbjerg, Peter Groth; Finco, Giovanni; et al. (2022)
    Nanomaterials
    High-contrast gratings (HCG) are an excellent candidate for label-free detection of various kinds of biomarkers because they exhibit sharp and sensitive optical resonances. In this work, we experimentally show the performance of pedestal HCG (PHCG), which is significantly enhanced in comparison with that of conventional HCG. PCHGs were found to provide a 11.2% improvement in bulk refractive index sensitivity, from 482 nm/RIU for the conventional design to 536 nm/RIU. The observed resonance was narrower, resulting in a higher Q-factor and figure of merit. By depositing Al2O3, HfO2, and TiO2 of different thicknesses as model analyte layers, surface sensitivity values were estimated to be 10.5% better for PHCG. To evaluate the operation of the sensor in solution, avidin was employed as a model analyte. For avidin detection, the surface of the HCG was first silanized and subsequently functionalized with biotin, which is well known for its ability to bind selectively to avidin. A consistent red shift was observed with the addition of each of the functional layers, and the analysis of the spectral shift for various concentrations of avidin made it possible to calculate the limit of detection (LoD) and limit of quantification (LoQ) for the structures. PHCG showed a LoD of 2.1 ng/mL and LoQ of 85 ng/mL, significantly better than the values 3.2 ng/mL and 213 ng/mL respectively, obtained with the conventional HCG. These results demonstrate that the proposed PHCG have great potential for biosensing applications, particularly for detecting and quantifying low analyte concentrations.
  • Experimental Demonstration of Entangled Photonic Qubits in a Continuous-Time Quantum Walk
    Item type: Other Conference Item
    Chapman, Robert J.; Häusler, Samuel; Finco, Giovanni; et al. (2023)
    2023 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)
    Photonic quantum walks (PQWs), realized in lattices of evanescently coupled waveguides, are a powerful platform for demonstrating quantum [1], topological [2] and localization phenomena [3]. The PQW dynamics are captured with a tight-binding Hamiltonian, whose parameters can be engineered with the geometry of the waveguide array. It has been proposed that the two-qubit controlled-NOT (CNOT) gate can be implemented by quantum interference of two-photons in a carefully engineered PQW [4]. Whereas photonic quantum logic gates typically rely on a network of beamsplitters [5], the PQW implements the quantum logic in a single step. While multi-photon experiments in PQWs have been demonstrated [1]–[3], where photon-photon bunching governs the dynamics, the controlled preparation of entangling logic gates is yet to be experimentally explored.
  • Large‐Scale Bottom‐Up Fabricated 3D Nonlinear Photonic Crystals
    Item type: Journal Article
    Vogler‐Neuling, Viola Valentina; Talts, Ülle‐Linda; Ferraro, Rebecca; et al. (2024)
    Advanced Photonics Research
  • On-chip quantum interference between independent lithium niobate-on-insulator photon-pair sources
    Item type: Working Paper
    Chapman, Robert James; Kuttner, Tristan; Kellner, Jost; et al. (2024)
    arXiv
    Generating and interfering non-classical states of light is fundamental to optical quantum in formation science and technology. Quantum photonic integrated circuits provide one pathway to wards scalability by combining nonlinear sources of non-classical light and programmable circuits in centimeter-scale devices. The key requirements for quantum applications include efficient genera tion of indistinguishable photon-pairs and high-visibility programmable quantum interference. Here, we demonstrate a lithium niobate-on-insulator (LNOI) integrated photonic circuit that generates a two-photon path-entangled state, and a programmable interferometer for quantum interference. We generate entangled photons with ∼ 2.3 × 108 pairs/s/mW brightness and perform quantum interference experiments on the chip with 96.8 ± 3.6 % visibility. LNOI is an emerging photonics technology that has revolutionized high-speed modulators and efficient frequency conversion. Our results provide a path towards large-scale integrated quantum photonics including efficient photon pair generation and programmable circuits for applications such as boson sampling and quantum communications.
  • High-Bandwidth Lithium Niobate Electro-Optic Modulator at Visible-Near-Infrared Wavelengths
    Item type: Conference Paper
    Pohl, David; Kellner, Jost; Kaufmann, Fabian; et al. (2022)
    OSA Technical Digest ~ European Conference on Optical Communication (ECOC) 2022
    Lithium niobate on insulator is presented as a platform for active integrated photonics at visible-near-infrared wavelengths. An electro-optic modulator operating at 780 nm featuring an electrical 3-dB bandwidth of 35 GHz and a halfwave voltage of 2.82 V is demonstrated, enabling transmission of a 40 Gbit/s on-off keying signal.
  • Lithium niobate-on-insulator integrated photonics for linear optical quantum computing
    Item type: Other Conference Item
    Chapman, Robert; Kuttner, Tristan; Kellner, Jost; et al. (2024)
    QuantuMatter 2024 Abstract Book
  • Interferometrically Coupled Reconfigurable Racetrack Resonator on Lithium Niobate-on-Insulator platform
    Item type: Conference Paper
    Maeder, Andreas; Kaufmann, Fabian; Finco, Giovanni; et al. (2022)
    OSA Technical Digest ~ European Conference on Optical Communication (ECOC) 2022
    We exploit a thermo-optically tuned interferometric coupling scheme to relax fabrication tolerances on coupling segments of microresonators in lithium niobate-on-insulator. We achieve extinction ratios up to 34 dB and show tuning of resonance bandwidth between 15 and 45 pm while maintaining extinction above 15 dB.
  • Nonlocal resonances in pedestal high-index-contrast metasurfaces based on a silicon-on-insulator platform
    Item type: Journal Article
    Franceschini, Paolo; Tognazzi, Andrea; Finco, Giovanni; et al. (2023)
    Applied Physics Letters
    Subwavelength control of the electromagnetic field distribution represents one of the current challenges in photonics research. In this field, diffractive metasurfaces with spatially extended (i.e., nonlocal) resonant modes have recently gained great interest for their versatility in molding the electromagnetic field beyond the approximation of independent resonators. In this framework, we design a high-contrast nonlocal metasurface featuring modes situated in the third operating spectral window of optical communications. The optical properties of the fabricated metasurface are investigated by linear spectroscopy and numerical simulations. Our analysis allows to discern the magnetic and electric nature of the bounded modes by means of polarization-resolved reflectance measurements. Our results represent a step toward integrated nano-photonics in the telecom regime and open promising opportunities for the development of compact nonlinear optical devices.
Publications 1 - 10 of 29