Fourier-domain OCT with undetected mid-infrared photons in the high-gain regime

Zotti, Giovanni (2024) Fourier-domain OCT with undetected mid-infrared photons in the high-gain regime. [Laurea magistrale], Università di Bologna, Corso di Studio in Physics [LM-DM270]
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Abstract

I present the first experimental implementation for Fourier-domain optical coherence tomography (OCT) using undetected mid-infrared photons in the high-gain regime. The core component is a custom-designed, aperiodically poled Potassium Titanyl Phosphate (KTiOPO4) crystal, enabling broadband parametric down-conversion (PDC) with high amplification. After discussing the theoretical background of classical OCT, nonlinear processes, PDC, and interference with undetected photons, I report the experimental performance of my setup. It achieves a typical signal-to-noise ratio (SNR) of ≈ 40 dB, axial resolution of ≈ 30 μm, depth range of ≈ 320 μm, and macroscopic lateral resolution of ≈ 3.3 mm. I demonstrate the setup’s capability to resolve real microstructures and its advantage over classical OCT in operating with samples obscured by a Germanium window. Additionally, I confirm the high-gain regime’s potential for strong signal power, allowing detection with standard Si power meters and time-gated measurements.

Abstract
Tipologia del documento
Tesi di laurea (Laurea magistrale)
Autore della tesi
Zotti, Giovanni
Relatore della tesi
Correlatore della tesi
Scuola
Corso di studio
Indirizzo
MATERIALS PHYSICS AND NANOSCIENCE
Ordinamento Cds
DM270
Parole chiave
OCT,MIR OCT,Nonlinear optics,Quantum optics,Interferometry
Data di discussione della Tesi
30 Ottobre 2024
URI

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