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Patrick Hendra

Publications and source records attributed to Patrick Hendra.

3 recordsLinked to original sources

Noise resilient real-time phase imaging via undetected light

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.

physics.optics

Rubidium-Doped KTiOPO$_4$ Waveguides as a Dual-Type Photon Pair Source

We investigate the dual generation of type-0 and type-II spontaneous parametric down conversions (SPDCs) within a single periodically poled rubidium-doped KTiOPO$_4$ (PPRKTP) waveguide. By coupling a 45 degree linearly polarized pump laser into the waveguide, both SPDC processes are concurrently excited: the type-0 SPDC process is facilitated via third-order quasi-phase matching (QPM) utilizing the nonlinear coefficient $d_{33}$ , while the type-II SPDC process employs first-order QPM with the nonlinear coefficient $d_{24}$. This dual-SPDC scheme holds potential for applications in quantum communication protocols targeting the telecommunication wavelength.

quant-ph

Photon Pair Source based on PPLN-Waveguides for Entangled Two-Photon Absorption

Fluorescence excitation by absorption of entangled photon pairs offers benefits compared to classical imaging techniques, such as the attainment of higher signal levels at low excitation power while simultaneously mitigating photo-toxicity. However, current entangled photon pair sources are unreliable for fluorescence detection. In order to address this limitation, there is a need for ultra-bright entangled photon pair sources. Among the potential solutions, sources utilizing nonlinear waveguides emerge as promising candidates to facilitate fluorescence excitation through entangled photons. In this paper, a source consisting of a periodically poled lithium niobate waveguide was developed and its key characteristics analysed. To demonstrate its suitability as key component for imaging experiments, the entangled two-photon absorption behavior of CdSe/ZnS quantum dot solutions was experimentally investigated.

quant-ph