Research & Projects

Here shows some brief of the research I am doing now or did before. Also some interesting course projects I did are shown below.

Benefitting from the high wave vector of evanescent wave illumination, the high spatial frequencies of an object can be shifted to the passband of a conventional imaging system, contributing subwavelength spatial information to the far-field image. In this project, we are going to utilize this approach on imaging of biological sample using a photonic chip illumination (build an on-chip imaging system) for faster imaging. I will also design and realize the algorithm of the imaging process based on iterative reconstruction and splicing on frequency domain, which is derived from Fourier Ptychography Microscopy(FPM). This work will lead to a paper.

This research was done during my research internship program (GREAT) in UC Davis. You can download the introduction slides of it here.

Electron cyclotron emission imaging (ECEI) and Microwave Imaging Reflectometry (MIR) diagnostics have been employed on a large number of magnetic fusion plasma confinement devices. The common approach is based on a Gaussian beam assumption, which generates good spatial resolution (centimeter level). The radial focal depth is limited by the poloidal resolution, comparable with Rayleigh length (~150 mm).

In contrast, I developed a new Bessel beam approach which is inspired by its application in area of biomedical imaging. With the property of propagation stability, Bessel beam is qualified to generate much longer focal depth. To test the new approach, I redesigned the DIII-D tokamak LCP ECEI optics using CODE V for upgrading into a Bessel beam approach based on an axicon lens. The achievable radial coverage can reach 300% of that of the current Gaussian approach according to the simulation result. Also I conducted a platform tes and verified the result. Based on this work, I have finished a paper (as the first author) under the instruction of the faculty and graduates of Millimeter-wave Research Center, UC Davis. This work has been published by Review of Scientific Instruments.

This research was done during my research training program of the college. In the diagnosis of clinical medicine, measuring the patient's blood characteristics and composition is a very important means, which is used to diagnose inflammation. The usual approach is to diagnose patients by taking blood samples from patients. However, a shortcoming of this approach is the lack of timeliness and simplicity, so that noninvasive or in-vivo detection is highly desirable. Based on the previous study of living blood detection technology and the principle of line array confocal microscopy, we have improved the overall design of the microscope, which makes the microscope device easier to use, and some imaging results were simulated with PIV tracer particles.

For the course project of Optoelectric Detection Technology & System, we investigated several methods of imaging through scattering media and performed simulation of one image restruction algorithm based on 'shower-curtain effect' [ref: Edrei, Eitan, and G. Scarcelli. "Optical imaging through dynamic turbid media using the Fourier-domain shower-curtain effect." Optica 3.1(2016):71.]. The process of retrieval operation is shown above. After dozens of iterations, the result can be acceptable (also dependable on roughness of the gournd glass). I wrote the MATLAB code and finally made a report of the simulation result to the teachers and classmates.

We developed a ray tracing & aberration calculating program using Qt 5.7 (C++) for the project in Computer Aided Optical System Design course. Based on the theories of geometrical optics, it can calculate some parameters in an optical system, such as the ideal image distance/height, field curvature, distortion, chromatic aberration, spherical aberration, coma aberration and so on. The curve of them can be generated as shown in the figure above. Also, users can use Excel to edit, import and export the lens parameter file. After finishing this project, our understanding of geometrical optics was greatly deepened. In this project, I served as the head of the group and for the outstanding design of this software, we achieved the highest grade in the class!

We use BRO ASAP optics software to simulate and research two classic naked-eye 3D display method: slit grating method and cylindrical lens method. We researched and compared the effect of screen size, screen resolution, desigend watching distance and watching angle and drew some conclusion: for example, the farther the designed watching distance is, the better the viewing result the user can achieve.

For the project of course Microprocessors & Interfacing, we designed a LED display cube called 'Opticube' which is composed of 8*8*8 RGB LEDs. It provides three games insided it and can be controlled using a smartphone with Blutooth connection. With some voice-recognition software's API, users can even use their voice to control it, and it can also answer simple questions asked by users with 'facial expression'. Also, with USB connection, the realtime display condition can be tranmitted to PC and showed in a software developed by us. The LED cube is controlled by a microprocessor and we use Keil C51 to write the display controlling code and develop game program. The PC software is developed by Qt, and the mobile remote controlling application by MIT App Inventor. For the outstanding performance of our project, we achieved the highest grade in this course!