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Full field optical coherence tomography (FF-OCT) has the advantage of ultrahigh lateral resolution (∼1 µm) resulting from a relatively high numerical aperture (NA) micro objective. However, usually the field of view of micro objective is limited. Furthermore, in vivo imaging, significant motion artifacts limit the performance of traditional FF-OCT where the quality of the restored image is generally degraded due to the influence of motion artifacts. In this paper, we propose a method of edge-preserving ptychography based on dual-balanced time domain FF-OCT, which we can call it time-domain ptychography full field optical coherence tomography (TD-POCT). The method combines the advantages of both ptychography and dual-balanced FF-OCT, which can overcome the limitation of the field for view of micro objective and suppresses motion blur. Moreover, this method can recover not only the amplitude of each layer, but also the phase information. So in addition to tomography, the system can also be used for surface 3D object reconstruction. Numerical simulation verifies that both the horizontal and vertical resolution can reach a few microns.

A real single-channel color image encryption method based on computational ghost imaging is proposed. Compared with the currently proposed color single-channel encryption scheme, the method does not decompose the color image into three gray-scale images or encode it into a grayscale image for encryption. Instead, the color speckle patterns are used as the key to directly encrypt. The ciphertext is a grayscale image and thus has camouflage properties to a certain extent. Furthermore, the optical encryption setup is easy to be implemented and the key is generated by a chaotic system, which not only guarantees security but also reduces the volume of key transmission. The feasibility and high security of this method are supported by both computer simulations and optical experiments.

An encryption method based on computational ghost imaging (CGI) with chaotic mapping and DNA encoding is proposed. To reduce the amount of keys in the CGI-based encryption system, the chaotic mapping algorithm is used to generate the random sequence as the speckle measurement matrix of CGI system. The measurement data of the bucket detector is subjected to block and DNA operations, which introduce the nonlinear characteristics in the encryption process. The problem of linear vulnerability of the encryption system has been greatly improved. Numerical simulation results show that, compared with the traditional CGI-based encryption method, the proposed method greatly reduces the amount of keys, increases the key space and enhances the security of the system.

Fourier-domain full-field optical coherence tomography has the advantages of high resolution and parallel detection. However, using parallel detection can result in optical crosstalk. Toward minimizing crosstalk, we implemented a very fast deformable membrane (DM) that introduces random phase illumination, which can effectively reduce the crosstalk by washing out fringes originating from multiply scattered light. However, although the application of DM has reduced the crosstalk problem in parallel detection to a certain extent, there will still be a lot of background noise, which may come from the circadian rhythm of the sample and multiple scattered photons. The problem could be solved by employing adaptive singular value decomposition (SVD) filtering. We also combined SVD with the cumulative sum method, which can significanlty improve image resolution. Also, the random phase introduced by DM in the spectral domain will cause axial crosstalk after an inverse Fourier transform. As far as we know, we are the first team to notice axial crosstalk and propose that this problem can be solved by controlling the deformation range of DM. We have carried out a theoretical analysis of the above methods and verified its feasibility by simulation.

Positron has attracted much attention in particle research for it was the first antiparticle discovered. Due to its extreme instability, positron is easy to annihilate with electron and release photons or form unstable positronium. Positron releases 1000 times more energy than nuclear fission of the same mass with no radioactive substance. As a new energy source, positron has more potential than other energy sources. With the rapid development of technology, the problem of how-to storage positron is solved gradually which makes a good foundation for annihilation of positron and electron beams. In this paper, the energy released by collision between electron and positron beams is deduced by theoretical analysis, based on the latest experimental results. The positron beam is the same energy of 10 MeV as the electron beam, which is adopt. After the pulses cross each other, the energy released is closed to 15mJ with current intensity 1020e+/s. The energy difference of different radius of pulses is studied. This work has great potential value in further research.

The potential and electric field responses in cylinder cavity with ceramics slice caused by distributed charge in X-ray environment were simulated with finite difference method. The numerical results indicate that the distributed charge in ceramics’ middle section is negative or positive, and positive of both sides. For the photon energies from 30 keV to 1 MeV with same fluence, distributed charge and electric field were decreased at first and then increased. Electrode has great effect to the potential and electric field responses. For different plating thickness, there exists minimum to the electric field amplitude, and for the plating, there exist optimal diameter and thickness. Distributed charge is calculated using Monte-Carlo particle transport code.

Aiming at the problem that the signal noise ratio (SNR) can’t meet the requirement due to electromagnetic interference in the measurement of coupling current of transmission cable core line in electromagnetic pulse environment, a shielded core line pulse current probe is designed and developed. This paper introduces the measuring principle of the probe, the structure characteristics and development situation, given the characteristics of the probe sensitivity and parameters, such as spectrum method and the calibration parameters, and analyzes its usage in the experimental results show that the design of shielded conductor pulse current probe based on the structure of the original transmission has a better ability to resist electromagnetic interference and pulse signal measurement capability.