Toward integrated sensors for optimized optical coherence tomography with undetected photons Roeder, Franz Pollmann, René Quiring, Viktor Eigner, Christof Brecht, Benjamin Silberhorn, Christine <jats:p> The development of practical sensors for optical coherence tomography (OCT) with undetected photons requires miniaturization via integration. To be practical, these sensors must exhibit a large spectral bandwidth and a high brightness, which are linked to a high axial resolution and a sufficient signal-to-noise ratio, respectively. Here, we combine these requirements in a scheme for OCT measurements with undetected photons based on nonlinear <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"> <a:mi>Ti</a:mi> <a:mo>:</a:mo> <a:msub> <a:mrow> <a:mi>Li</a:mi> <a:mi>Nb</a:mi> <a:mi mathvariant="normal">O</a:mi> </a:mrow> <a:mn>3</a:mn> </a:msub> </a:math> waveguides. We investigate the performance benchmarks of the commonly used SU(1,1) scheme in comparison to an induced-coherence scheme and find that the latter is actually better suited when implementing measurements with undetected photons in integrated systems. In both schemes, we perform pump-gain optimization and OCT measurements with undetected photons with an axial resolution as low as <d:math xmlns:d="http://www.w3.org/1998/Math/MathML" display="inline"> <d:mn>28</d:mn> <d:mspace width="0.2em"/> <d:mtext fontfamily="times">μ</d:mtext> <d:mrow> <d:mi mathvariant="normal">m</d:mi> </d:mrow> </d:math> . </jats:p> American Physical Society (APS) 2026 info:eu-repo/semantics/article doc-type:article text http://purl.org/coar/resource_type/c_6501 https://ris.uni-paderborn.de/record/65094 Roeder F, Pollmann R, Quiring V, Eigner C, Brecht B, Silberhorn C. Toward integrated sensors for optimized optical coherence tomography with undetected photons. <i>Physical Review Applied</i>. 2026;25(3). doi:<a href="https://doi.org/10.1103/cwsx-42c4">10.1103/cwsx-42c4</a> eng info:eu-repo/semantics/altIdentifier/doi/10.1103/cwsx-42c4 info:eu-repo/semantics/altIdentifier/issn/2331-7019 info:eu-repo/semantics/closedAccess