No Arabic abstract
Compared with two-dimensional imaging, three-dimensional imaging is much more advantageous to catch the characteristic information of the target for remote sensing. We report a range-resolving ghost imaging ladar system together with the experimental demonstration of three-dimensional remote sensing with a large field of view. The experiments show that, by measuring the correlation function of intensity fluctuations between two light fields, a three-dimensional map at about 1.0 km range with 25 cm resolution in lateral direction and 60 cm resolution in axial direction has been achieved by time-resolved measurements of the reflection signals.
In quantum mechanics, entanglement and correlations are not just a mere sporadic curiosity, but rather common phenomena at the basis of an interacting quantum system. In electron microscopy, such concepts have not been extensively explored yet in all their implications; in particular, inelastic scattering can be reanalyzed in terms of correlation between the electron beam and the sample. While classical inelastic scattering simply implies loss of coherence in the electron beam, performing a joint measurement on the electron beam and the sample excitation could restore the coherence and the lost information. Here, we propose to exploit joint measurement in electron microscopy for a surprising and counter-intuitive application of the concept of ghost imaging. Ghost imaging, first proposed in quantum photonics, can be applied partially in electron microscopy by performing joint measurement between the portion of the transmitted electron beam and a photon emitted from the sample reaching a bucket detector. This would permit us to form a one-dimensional virtual image of an object that even has not interacted with the electron beam directly. This technique is extremely promising for low-dose imaging that requires the minimization of radiation exposure for electron-sensitive materials, because the object interacts with other form of waves, e.g., photons/surface plasmon polaritons, and not the electron beam. We demonstrate this concept theoretically for any inelastic electron-sample interaction in which the electron excites a single quantum of a collective mode, such as a photon, plasmon, phonon, magnon, or any optical polariton.
We investigate the effect of turbulence on quantum ghost imaging. We use entangled photons and demonstrate that for a novel experimental configuration the effect of turbulence can be greatly diminished. By decoupling the entangled photon source from the ghost imaging central image plane, we are able to dramatically increase the ghost image quality. When imaging a test pattern through turbulence, this method increased the imaged pattern visibility from V = 0.14 +/- 0.04 to V = 0.29 +/- 0.04.
Fourier analysis of ghost imaging (FAGI) is proposed in this paper to analyze the properties of ghost imaging with thermal light sources. This new theory is compatible with the general correlation theory of intensity fluctuation and could explain some amazed phenomena. Furthermore we design a series of experiments to verify the new theory and investigate the inherent properties of ghost imaging.
As one of important analysis tools, microscopes with high spatial resolution are indispensable for scientific research and medical diagnosis, and much attention is always focused on the improvement of resolution. Over the past decade, a novel technique called ghost imaging has been developed that may provide a new approach toward increasing the resolution of an imaging system. In this paper, we introduce this technique into microscopes for the first time and report a proof-of-principle experimental demonstration of a microscope scheme based on ghost imaging.
Quantum - or classically correlated - light can be employed in various ways to improve resolution and measurement sensitivity. In an interaction-free measurement, a single photon can be used to reveal the presence of an object placed within one arm of an interferometer without being absorbed by it. This method has previously been applied to imaging. With a technique known as ghost imaging, entangled photon pairs are used for detecting an opaque object with significantly improved signal-to-noise ratio while preventing over-illumination. Here, we integrate these two methods to obtain a new imaging technique which we term interaction-free ghost-imaging that possesses the benefits of both techniques. While maintaining the image quality of conventional ghost-imaging, this new technique is also sensitive to phase and polarisation changes in the photons introduced by a structured object. Furthermore, thanks to the interaction-free nature of this new technique, it is possible to reduce the number of photons required to produce a clear image of the object (which could be otherwise damaged by the photons) making this technique superior for probing light-sensitive materials and biological tissues.