Towards quantum 3d imaging devices

We review the advancement of the research toward the design and implementation of quantum plenoptic cameras, radically novel 3D imaging devices that exploit both momentum–position entanglement and photon–number correlations to provide the typical refocusing and ultra-fast, scanning-free, 3D imaging capability of plenoptic devices, along with dramatically enhanced performances, unattainable in standard plenoptic cameras: diffraction-limited resolution, large depth of focus, and ultra-low noise. To further increase the volumetric resolution beyond the Rayleigh diffraction limit, and achieve the quantum limit, we are also developing dedicated protocols based on quantum Fisher information. However, for the quantum advantages of the proposed devices to be effective and appealing to end-users, two main challenges need to be tackled. First, due to the large number of frames required for correlation measurements to provide an acceptable signal-to-noise ratio, quantum plenoptic imaging (QPI) would require, if implemented with commercially available high-resolution cameras, acquisition times ranging from tens of seconds to a few minutes. Second, the elaboration of this large amount of data, in order to retrieve 3D images or refocusing 2D images, requires high-performance and time-consuming computation. To address these challenges, we are developing high-resolution single-photon avalanche photodiode (SPAD) arrays and high-performance low-level programming of ultra-fast electronics, combined with compressive sensing and quantum tomography algorithms, with the aim to reduce both the acquisition and the elaboration time by two orders of magnitude. Routes toward exploitation of the QPI devices will also be discussed

Fast and high-resolution Correlation Plenoptic Imaging between Arbitrary Planes

We present a novel approach to Correlation Plenoptic Imaging (CPI), named CPI between arbitrary planes. This approach allows a tridimensional reconstruction of the scene around two distinct arbitrary planes conjugate to the correlated sensors

X-ray detection by direct modulation of losses in a laser cavity

In this work, we experimentally explore the possibility to realize a sensor whose basic building block is a laser cavity that hosts a target crystal for the incident ionizing radiation. Two possible detection mechanisms are considered: a process of coherent scintillation related to the rapid decay via stimulated emission of the excited atomic or molecular levels of the target material and the activation of states that absorb intracavity photons. We use a solid-state laser to study the dynamic response of our prototype sensor and the related intrinsic limitations and demonstrate capability to detect x-ray energy down to 10 GeV

High infrared light yield of Erbium-doped fluoride crystals

The emission spectrum of Erbium-doped fluoride crystals excited by soft X-rays in the (400\u20131700) nm wave-length range is investigated between 3.2 K and 300 K. The largest component of the crystals emission is observed in the infrared range, which corresponds to a light yield of several tens of photons/keV. Such a large value is caused by energy transfer processes between the Erbium ions which convert the excitation of a dopant ion at high energies into the emission of multiple infrared photons. The present results show that this mechanism could be exploited to realize scintillators of high light yield

Correlation light-field microscopy

We present a novel approach to three-dimensional optical microscopy, named correlation light-field microscopy (CLM). This approach is based on correlation plenoptic imaging and exploits correlations between intensity fluctuations, intrinsic in chaotic light, to retrieve both spatial information about the intensity distribution of light on the sample and angular information about the directions of propagation of the light rays. Such a plenoptic (or light-field ) information about the sample enables an extension of the natural depth of field, while avoiding the intrinsic loss of spatial resolution occurring in conventional light-field microscopy. We discuss the capability of CLM of refocusing out-of-focus planes of the sample, paving the way to scanning-free three-dimensional reconstruction while keeping the at-focus resolution at the diffraction limit showing a brief comparison with light-field microscopy. Finally we discuss the perspective of improvements in CLM acquisition speed by the integration of SPAD array sensors in the setup

Plenoptic microscopy and photography from intensity correlations

We present novel methods to perform plenoptic imaging at the diffraction limit by measuring intensity correlations of light. The first method is oriented towards plenoptic microscopy, a promising technique which allows refocusing and depth-of-field enhancement, in post-processing, as well as scanning free 3D imaging. To overcome the limitations of standard plenoptic microscopes, we propose an adaptation of Correlation Plenoptic Imaging (CPI) to the working conditions of microscopy. We consider and compare different architectures of CPI microscopes, and discuss the improved robustness with respect to previous protocols against turbulence around the sample. The second method is based on measuring correlations between the images of two reference planes, arbitrarily chosen within the tridimensional scene of interest, providing an unprecedented combination of image resolution and depth of field. The results lead the way towards the realization of compact designs for CPI devices