Quantum techniques are commonly used to enhance measurement performance in many fields, such as imaging, microscopy, communications, computing and metrology. In quantum imaging and microscopy, entangled photons are exploited to improve image resolution and sensitivity, overcoming the diffraction limit and providing Sub-Shot Noise (SSN) measurements [1] . Super resolution imaging, SSN imaging, quantum-enhanced displacement sensing, correlation plenoptic imaging and ghost imaging are different quantum techniques used to enhance image quality. All them require time-resolved single-photon detectors, capable to detect photon coincidences with sub-nanosecond precision.
Quantum techniques are commonly used to enhance measurement performance in many fields, such as imaging, microscopy, communications, computing and metrology. In quantum imaging and microscopy, entangled photons are exploited to improve image resolution and sensitivity, overcoming the diffraction limit and providing Sub-Shot Noise (SSN) measurements [1] . Super resolution imaging, SSN imaging, quantum-enhanced displacement sensing, correlation plenoptic imaging and ghost imaging are different quantum techniques used to enhance image quality. All them require time-resolved single-photon detectors, capable to detect photon coincidences with sub-nanosecond precision.
We will show that photon correlations can be employed to overcome the typical limitations of conventional plenoptic imaging devices, thus leading to quantum-enhanced plenoptic imaging. In particular, we will show an unprecedented combination of resolution and depth of field combined with refocusing capability and depth extension. We will show experimental results obtained in different application scenarios, ranging from microscopy to photography-like protocols. Significant advances in acquisition speed will also be discussed, as achieved by both hardware (e.g., use of SPAD arrays, as opposed to common CMOS and CCD cameras) and software (e.g., compressive sensing, quantum tomography) solutions.
Summary form only given. In the last years several proof of principle experiments have demonstrated the advantages of quantum technologies respect to classical schemes in imaging, metrology and sensing. The present challenge is to overcome the limits of proof of principle demonstrations to approach real applications. Here, we present the such an achievement in the field of quantum enhanced imaging. In particular, we describe the realization of a sub-shot-noise (SSN) wide field microscope (see Ref. [1]), based on spatially multi-mode non-classical photon number correlations [2]. The microscope produces real-time images of 8000 pixels at full resolution, for (500μm)2field-of-view, with noise reduced at 80% of the shot noise level in each pixel. This is suitable for absorption imaging of complex structures, like biological samples. By simple post-elaboration, specifically applying a “quantum enhanced median filter”, the noise is further reduced (less than 30% of the shot noise level) by setting a trade-off with the resolution. It realizes the best sensitivity per incident photon ever achieved in absorption microscopy.
We introduce a new generation of 3D imaging devices based on quantum plenoptic imaging. Position-momentum entanglement and photon number correlations are exploited to provide a scan-free 3D image after post-processing of the collected light intensity signal. We explore the steps toward designing and implementing quantum plenop- tic cameras with dramatically improved performances, unattainable in standard plenoptic cameras, such as diffraction-limited resolution, large depth of focus, and ultra-low noise. However, to make these new types of devices attractive to end-users, two main challenges need to be tackled: the reduction of the acquisition times, that for the commercially available high-resolution cameras would be from tens of seconds to a few minutes, and a speed-up in processing the large amount of data that are acquired, in order to retrieve 3D reconstructions or refocused 2D images. To address these challenges, we are employing high-resolution SPAD (single photon avalanche diode) arrays and high-performance low-level programming of ultra-fast electronics, combined with compressive sensing and quantum tomography algorithms, with the aim of reducing both the acquisition and the elaboration time by one or possibly two orders of magnitude. Moreover, in order to achieve the quantum limit and further increase the volumetric resolution beyond the Rayleigh diffraction limit, we explored dedicated pro- tocols based on quantum Fisher information. Finally, we discuss how this new generation of quantum plenoptic devices could be exploited in different fields of research, such as 3D microscopy and space imaging.
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.
The emerging field of quantum imaging introduces new methods to overcome classical limitations in optical microscopy. A detection apparatus capable of analyzing the quantum signature of light, is a crucial component in the heart of any such method. We present a novel quantum imaging modality, based on a state-of-the-art single photon avalanche diode (SPAD) array in a confocal setup. This modality enables unprecedented simplicity and scalability in imaging temporal photon correlations. We demonstrate the potential of this approach by measuring temporal correlations of classical and quantum sources, as well as demonstrate a quantum super-resolution technique.
Quantum-enhanced metrology techniques offer ultra-precise timekeeping, allowing for breakthroughs in navigation systems, global positioning, medical and Biological imaging. Quantum metrology, a core application of quantum technologies, leverages non-classical states of light (such as entanglement and squeezing) to enhance measurement precision, sensitivity, and resolution beyond the classical limits, particularly the shot-noise limit. Its application to bio imaging and microscopy offers significant advantages for studying delicate biological specimens, which are often susceptible to damage from the intense light typically required by conventional high-resolution methods. The abstract highlights the potential of quantum properties of light to revolutionize bio imaging by providing a non-invasive, highly sensitive, and high-resolution platform for observing biological processes at fundamental scales.