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arXiv:2208.03005 · Optics Express

Phase-quadrature quantum imaging with undetected photons

Björn Haase, Joshua Hennig, Mirco Kutas, Erik Hagen Waller, Julian Hering, Georg von Freymann, Daniel Molter

Published Oct 12, 2022• 23 citations
arXivHTMLPDF

Abstract

Sensing with undetected photons allows access to spectral regions with simultaneous detection of photons of another region and is based on nonlinear interferometry. To obtain the full information of a sample, the corresponding interferogram has to be analyzed in terms of amplitude and phase, which has been realized so far by multiple measurements followed by phase variation. Here, we present a polarization-optics-based phase-quadrature implementation in a nonlinear interferometer for imaging with undetected photons in the infrared region. This allows us to obtain phase and visibility with a single image acquisition without the need of varying optical paths or phases, thus enabling the detection of dynamic processes. We demonstrate the usefulness of our method on a static phase mask opaque to the detected photons as well as on dynamic measurement tasks as the drying of an isopropanol film and the stretching of an adhesive tape.

DOI
10.1364/oe.471837

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Sensing with undetected photons allows access to spectral regions with simultaneous detection of photons of another region and is based on nonlinear interferometry. To obtain the full information of a sample, the corresponding interferogram has to be analyzed in terms of amplitude and phase, which has been realized so far by multiple measurements followed by phase variation. Here, we present a polarization-optics-based phase-quadrature implementation in a nonlinear interferometer for imaging with undetected photons in the infrared region. This allows us to obtain phase and visibility with a single image acquisition without the need of varying optical paths or phases, thus enabling the detection of dynamic processes. We demonstrate the usefulness of our method on a static phase mask opaque to the detected photons as well as on dynamic measurement tasks as the drying of an isopropanol film and the stretching of an adhesive tape.
Quantum imaging with undetected light has recently emerged as a technique in which quantum correlations and nonlinear interferometry are combined to decouple illumination and detection paths. This approach has been more recently extended and combined with digital phase-shifting holography and off-axis holography to extract both the amplitude and phase information of a sample relying on single-photon interference. Despite these advantages, implementing the technique in real-world scenarios where the observed system is subject to environmental noise and dynamic variations remains challenging. The primary limitation lies in the inability of quantum imaging systems to retrieve object information in real time under high-noise conditions. Here, we experimentally demonstrate real-time amplitude and phase imaging in noisy environments, building upon our previous implementation of quantum off-axis holography. Our results demonstrate real-time imaging at acquisition rates up to 4~Hz, even when the noise level exceeds the signal by an order of magnitude.
Quantum sensing in the infrared regime often demands the use of expensive and cryogenically operated detectors. Nonlinear interferometry has paved the way for information transfer from the infrared to the near--infrared or visible regime in various quantum technologies. A particularly interesting application of these interferometers involves spectrally--resolved quantum imaging using undetected photons, enabled by the use of temperature--tunable parametric amplifiers. In this work, we demonstrate spectrally resolved transmission imaging with undetected photons around 1550 nm using a spontaneous parametric down conversion based folded nonlinear interferometric scheme, registering the attenuation of a zebrafish larva as a biological feasibility test. We characterize and calibrate the interferometer, having achieved spectrally resolved interference fringes with a maximum baseline visibility of ∼74%\sim 74\%∼74% in the near--infrared regime. Phase--stepped readout of a grating spectrometer gives a resolving power of ∼1460\sim1460∼1460 (from the spectrometer's point spread function) at 1550 nm, and ∼730\sim 730∼730 from the coherence length, the finest reported for imaging with undetected photons, over an instantaneous spectral window of ≈51\approx 51≈51 cm−1^{-1}−1.
Imaging with undetected photons (IUP) enables the possibility of sensing changes in the phase and the transmission of a beam of light that need never be detected. This has led to the possibility of infrared sensing with visible silicon camera technology, for example. Relying on the interference of two identical pairs of photons, IUP was initially achieved using unidirectional paths through two nonlinear crystal pair sources. More recently, folded arrangements using bidirectional paths through a single-crystal have become common for their simplicity. Here, we theoretically model and experimentally implement a novel setup involving three interference paths through a single nonlinear crystal. This establishes two independent IUP sensing modes in addition to a third linear interference mode. We achieve this using a polarization state quantum eraser approach, with excellent agreement between experiment and theory. This system provides a new route to control and optimize IUP interference in a single-crystal folded arrangement by using controllable quantum erasure to balance the interferometer, opening the door to new implementations and applications for IUP.
Quantum imaging with undetected photons (QIUP) is an active imaging method in which the detected and the probing photons are distinct and can be selected from different spectral regions. This technique holds potential for a wide range of applications affected by the trade-off between illumination wavelength and detection efficiency. The state-of-the-art experimental configurations assess the spectral absorption and phase information of a target solely in a transmissive configuration, which presents a limitation for applications where the target cannot be aligned with optical elements positioned behind it. In this work, we present an experimental configuration for QIUP of a scattering target, aiming to fill the gap in the applicability of the QIUP technique and enabling QIUP to detect remote targets.
Quantum imaging with undetected light (QIUL) can retrieve amplitude and phase information of an object by exploiting the quantum correlations of photon-pairs generated through spontaneous parametric down conversion (SPDC), where the illumination and detection can be carried at very distinct wavelength ranges. This fact allows to benefit from a mature detection technology in the visible spectral range, while probing the object at a more exotic wavelength. Here we experimentally implement a QIUL approach with Fourier off-axis holography in a hybrid-type induced-coherence non-linear interferometer. Our approach reconstructs the amplitude and phase information of an object with a single shot in a wide-field configuration, being an alternative in front of techniques that require multiple acquisition frames, such as phase-shifting holography.