We examine a novel diagnostic method suitable for optical biopsy, i.e., the noninvasive in vivo detection of malignant lesions in human tissue. Entangled-photon imaging is an emerging technology based upon the use of non-classical sources of light such as optical parametric oscillators (OPO). These sources generate above-threshold signal and idler beams that have intensity fluctuations highly correlated in space and time (twin beams). It has been shown that low-intensity OPO's make possible high sensitivity absorption measurements of weak targets, below the shot- noise limit. The direct use of this technology for optical biopsy is severely restricted by the large amount of scattering noise associated with light-tissue interaction. We report what is, to our knowledge, the first feasibility study on a differential wavelength, OPO-based setup targeted for mammography. Constraints related to the entanglement time, OPO selection and background suppression are analyzed. The paper concludes with a review of future developments and challenges.
We examine a novel diagnostic method suitable for optical biopsy, i.e., the noninvasive in vivo detection of malignant lesions in human tissue. Entangled-photon imaging is an emerging technology based upon the use of non-classical sources of light such as optical parametric oscillators (OPO). These sources generate above-threshold signal and idler beams that have intensity fluctuations highly correlated in space and time (twin beams). It has been shown that low-intensity OPO's make possible high sensitivity absorption measurements of weak targets, below the shot- noise limit. The direct use of this technology for optical biopsy is severely restricted by the large amount of scattering noise associated with light-tissue interaction. We report what is, to our knowledge, the first feasibility study on a differential wavelength, OPO-based setup targeted for mammography. Constraints related to the entanglement time, OPO selection and background suppression are analyzed. The paper concludes with a review of future developments and challenges.
In this work a quantum imaging setup based on undetected squeezed photons is employed for metrological applications such as sensitive phase measurement and quantum imaging. Unlike traditional quantum imaging with undetected photons, as introduced by A. Zeilinger et al., the proposed setup incorporates a homodyne detection system and enhances the brightness of the quantum light using optical parametric oscillators (OPOs). The inclusion of OPOs may challenge the validity of the low-gain approximation, necessitating the development of a new theoretical framework that extends beyond this approximation. The results demonstrate a higher signal-to-noise ratio, which serves as a key metric for both image quality and phase-measurement accuracy. Furthermore, an imaging protocol is introduced to effectively suppress background noise. Notably, this protocol enables the extraction of image information encoded in quantum fluctuations (noise), paving the way for non-disruptive imaging. This is particularly significant in the field of bio-imaging, since the object (a sensitive living cell) is interrogated by longer-wavelength idler light while detection is applied at optical frequency in which the sensors are less noisy and has more quantum efficiency.
In this work a quantum imaging setup based on undetected squeezed photons is employed for metrological applications such as sensitive phase measurement and quantum imaging. In spite of the traditional quantum imaging with undetected photons, introduced by A. Zeilinger et. al, the proposed setup is equipped by a homodyne detection and also the brightness of the quantum light is enhanced by an optical parametric oscillator (OPO). Introducing OPO may be diminish the validity of the low gain approximation, so a theoretical approach beyond this approximation is introduced. Due to the resource of squeezing, the results reveal the higher amount of signal to noise ratio, as a measure of image quality and phase-measurement accuracy. Accordingly, an imaging protocol is introduced to suppress the background noises, effectively. Interestingly, This protocol provides a way to extract the image information which is encoded in the quantum fluctuation (noise). Therefore, non-disruptive imaging is achievable, which is noteworthy subject in the field of bio-imaging of sensitive and low damage threshold living cells.
Non-invasive cancer diagnostics aim to detect tumors as early as possible without harming the patient. In this project, I explore how quantum photonics can improve medical imaging by using the quantum properties of light to reach subcellular precision. The main idea is to compare classical optical coherence tomography (OCT) with quantum-enhanced imaging that uses single photons, entangled photon pairs, and squeezed-light states. Using a conceptual device model, I examine how quantum light sources could reduce photonic noise, improve contrast, and allow repeated imaging with minimal damage to sensitive tissues. Literature on quantum imaging, biophotonics, and cancer diagnostics is reviewed to connect these ideas to current research in early tumor detection. These studies report gains in axial resolution, depth penetration, and signal-to-noise ratio when quantum effects are used. The project also considers ethical questions, such as fair access, cost, and data privacy, when introducing advanced quantum technologies into healthcare. Overall, the work suggests that quantum photonics can help build safer, faster, and more accurate imaging systems for cancer diagnostics, while supporting responsible and inclusive medical innovation.
Nondegenerate optical parametric oscillators generate above-threshold signal and idler beams that have intensity fluctuations correlated at the quantum level (twin beams). We describe what is to our knowledge the first high-sensitivity spectroscopy experiment using twin beams emitted by a cw optical parametric oscillator: a very weak two-photon absorption signal, in the 10(-7) range, is recorded on the 4S(1/2)-5S(1/2) transition of atomic potassium with a noise background that is reduced by 1.9 dB with respect to the shot-noise limit of the light used in the experiment.
Laser confocal imaging technology has become an important analytical tool in biological, biomedical, and materials science research, offering high imaging precision. However, this technology still has some limitations, especially in imaging biological samples (such as living tissues or cells), where the high intensity of the laser may cause irreversible photodamage. It has been proposed that quantum entangled light sources, instead of laser, can be used to avoid this drawback. In this paper, we experimentally demonstrated a quantum confocal imaging technology employing entangled photon sources with high brightness and stability. In the experiment, we obtained the point-by-point scanning imaging of a targeted area, in which a resolution of 3.91 µm is achieved and the signal-to-noise ratio (SNR) degradation is suppressed. We also theoretically analyzed the potential of quantum confocal imaging to improve SNR performance in photodamage-free imaging. Our results could widen the application fields of confocal imaging technology and pave the way for applying the quantum technology in biological imaging.
Entangled photon quantum imaging technology has become very promising for marine imaging due to its high resolution, anti-turbulence, and anti-interference properties. The turbulence and optical attenuation caused by oceanic water would impose severe limitations on conventional imaging equipment. Quantum imaging based on entangled light sources could make it possible to overcome the constraints of low imaging resolution, large maritime environmental impact and low confidentiality in traditional underwater target imaging. Hence, the recent technological developments in terms of quantum imaging in free space motivate our investigation into high-resolution quantum imaging based on spatially correlated properties of entangled photon pairs in a marine environment. Moreover we propose and design an innovative underwater quantum imaging optical path for experimental verification. We conduct extensive experiments to assess the effectiveness of our proposed quantum imaging approach in marine environments. In order to solve the problem of the slow quantum imaging process, we propose an innovative compressive sensing reconstruction algorithm. Experiments show that the compressive sensing method could be utilized to reduce the imaging time. Finally, we propose an underwater quantum target identification method based on deep learning, further providing the possibility for underwater quantum target identification of entangled light sources.