Yang Shi

Bio: Yang Shi is an academic researcher from Wuhan University. The author has contributed to research in topics: Nanotechnology & Optical tweezers. The author has an hindex of 8, co-authored 10 publications receiving 204 citations. Previous affiliations of Yang Shi include Jinan University.

Optofluidic marine phosphate detection with enhanced absorption using a Fabry–Pérot resonator

Abstract: Real-time detection of phosphate has significant meaning in marine environmental monitoring and forecasting the occurrence of harmful algal blooms. Conventional monitoring instruments are dependent on artificial sampling and laboratory analysis. They have various shortcomings for real-time applications because of the large equipment size and high production cost, with low target selectivity and the requirement of time-consuming procedures to obtain the detection results. We propose an optofluidic miniaturized analysis chip combined with micro-resonators to achieve real-time phosphate detection. The quantitative water-soluble components are controlled by the flow rate of the phosphate solution, chromogenic agent A (ascorbic acid solution) and chromogenic agent B (12% ammonium molybdate solution, 80% concentrated sulfuric acid and 8% antimony potassium tartrate solution with a volume ratio of 80 : 18 : 2). Subsequently, an on-chip Fabry–Perot microcavity is formed with a pair of aligned coated fiber facets. With the help of optical feedback, the absorption of phosphate can be enhanced, which can avoid the disadvantages of the macroscale absorption cells in traditional instruments. It can also overcome the difficulties of traditional instruments in terms of size, parallel processing of numerous samples and real-time monitoring, etc. The absorption cell length is shortened to 300 μm with a detection limit of 0.1 μmol L−1. The time required for detection is shortened from 20 min to 6 seconds. Predictably, microsensors based on optofluidic technology will have potential in the field of marine environmental monitoring.

Optical Fiber Tweezers: A Versatile Tool for Optical Trapping and Manipulation.

Abstract: Optical trapping is widely used in different areas, ranging from biomedical applications, to physics and material sciences. In recent years, optical fiber tweezers have attracted significant attention in the field of optical trapping due to their flexible manipulation, compact structure, and easy fabrication. As a versatile tool for optical trapping and manipulation, optical fiber tweezers can be used to trap, manipulate, arrange, and assemble tiny objects. Here, we review the optical fiber tweezers-based trapping and manipulation, including dual fiber tweezers for trapping and manipulation, single fiber tweezers for trapping and single cell analysis, optical fiber tweezers for cell assembly, structured optical fiber for enhanced trapping and manipulation, subwavelength optical fiber wire for evanescent fields-based trapping and delivery, and photothermal trapping, assembly, and manipulation.

A liquid thermal gradient refractive index lens and using it to trap single living cell in flowing environments

Abstract: A gradient refractive index (GRIN) lens has a great potential for on-chip imaging and detection systems because of its flat surface with reduced defects. This paper reports a liquid thermal GRIN lens prepared using heat conduction between only one liquid, and uses it as a tunable optical tweezer for single living cell trapping in a flowing environment. This liquid GRIN lens consists of a trapezoidal region in the upper layer which is used to establish a GRIN profile by the heat conduction between three streams of benzyl alcohol with different temperatures, and subsequently a rhombus region in the lower layer with compensation liquids to form a steady square-law parabolic refractive index profile only in transverse direction. Simulations and experiments successfully show the real-time tunability of the focusing properties. The focal length can be modulated in the range of 500 μm with the minimum focal length of 430 μm. A considerable high enhancement factor achieves 5.4 whereas the full width at half maximum is 4 μm. The response time of the GRIN lens is about 20 ms. Based on this enhancement, tunable optical trapping for single human embryonic kidney 293 cell in the range of 280 μm is demonstrated by varying the focal length and working distance which is difficult for solid optical tweezers. The considerable quality of this liquid GRIN lens indicates on-chip applications especially in high quality optical imaging, detection and cells' handling.

Optically Controlled Living Micromotors for the Manipulation and Disruption of Biological Targets

Abstract: Bioinspired and biohybrid micromotors represent a revolution in microrobotic research and are playing an increasingly important role in biomedical applications. In particular, biological micromotors that are multifunctional and can perform complex tasks are in great demand. Here, we report living and multifunctional micromotors based on single cells (green microalgae: Chlamydomonas reinhardtii) that are controlled by optical force. The micromotor's locomotion can be carefully controlled in a variety of biological media including cell culture medium, saliva, human serum, plasma, blood, and bone marrow fluid. It exhibits the capabilities to perform multiple tasks, in particular, indirect manipulation of biological targets and disruption of biological aggregates including in vitro blood clots. These micromotors can also act as elements in reconfigurable motor arrays where they efficiently work collaboratively and synchronously. This work provides new possibilities for many in vitro biomedical applications including target manipulation, cargo delivery and release, and biological aggregate removal.

Optofluidics: the interaction between light and flowing liquids in integrated devices

Abstract: Optofluidics is a rising technology that combines microfluidics and optics. Its goal is to manipulate light and flowing liquids on the micro/nanoscale and exploiting their interaction in optofluidic chips. The fluid flow in the on-chip devices is reconfigurable, non-uniform and usually transports substances being analyzed, offering a new idea in the accurate manipulation of lights and biochemical samples. In this paper, we summarized the light modulation in heterogeneous media by unique fluid dynamic properties such as molecular diffusion, heat conduction, centrifugation effect, light-matter interaction and others. By understanding the novel phenomena due to the interaction of light and flowing liquids, quantities of tunable and reconfigurable optofluidic devices such as waveguides, lenses, and lasers are introduced. Those novel applications bring us firm conviction that optofluidics would provide better solutions to high-efficient and high-quality lab-on-chip systems in terms of biochemical analysis and environment monitoring.

Fundamentals of optical waveguides

Abstract: Preface 1. Wave Theory of Optical Waveguides 2. Planar Optical Waveguides 3. Optical Fibers 4. Couple Mode Theory 5. Nonlinear Optical Effects in Optical Fibers 6. Finite Element Method 7. Beam Propagation Method 8. Staircase Concatention Method 9. Planar Lightwave Circuits 10. Theorems and Formulas Appendix

Optical trapping with structured light: a review

Abstract: Optical trapping describes the interaction between light and matter to manipulate micro-objects through momentum transfer. In the case of 3D trapping with a single beam, this is termed optical tweezers. Optical tweezers are a powerful and noninvasive tool for manipulating small objects, and have become indispensable in many fields, including physics, biology, soft condensed matter, among others. In the early days, optical trapping was typically accomplished with a single Gaussian beam. In recent years, we have witnessed rapid progress in the use of structured light beams with customized phase, amplitude, and polarization in optical trapping. Unusual beam properties, such as phase singularities on-axis and propagation invariant nature, have opened up novel capabilities to the study of micromanipulation in liquid, air, and vacuum. We summarize the recent advances in the field of optical trapping using structured light beams.

Optical Forces: From Fundamental to Biological Applications.

Abstract: Optical forces, generally arising from changes of field gradients or linear momentum carried by photons, form the basis for optical trapping and manipulation. Advances in optical forces help to reveal the nature of light-matter interactions, giving answers to a wide range of questions and solving problems across various disciplines, and are still yielding new insights in many exciting sciences, particularly in the fields of biological technology, material applications, and quantum sciences. This review focuses on recent advances in optical forces, ranging from fundamentals to applications for biological exploration. First, the basics of different types of optical forces with new light-matter interaction mechanisms and near-field techniques for optical force generation beyond the diffraction limit with nanometer accuracy are described. Optical forces for biological applications from in vitro to in vivo are then reviewed. Applications from individual manipulation to multiple assembly into functional biophotonic probes and soft-matter superstructures are discussed. At the end future directions for application of optical forces for biological exploration are provided.

Full-angle tomographic phase microscopy of flowing quasi-spherical cells.

Abstract: We report a reliable full-angle tomographic phase microscopy (FA-TPM) method for flowing quasi-spherical cells along microfluidic channels. This method lies in a completely passive optical system, i.e. mechanical scanning or multi-direction probing of the sample is avoided. It exploits the engineered rolling of cells while they are flowing along a microfluidic channel. Here we demonstrate significant progress with respect to the state of the art of in-flow TPM by showing a general extension to cells having almost spherical shapes while they are flowing in suspension. In fact, the adopted strategy allows the accurate retrieval of rotation angles through a theoretical model of the cells' rotation in a dynamic microfluidic flow by matching it with phase-contrast images resulting from holographic reconstructions. So far, the proposed method is the first and the only one that permits to get in-flow TPM by probing the cells with full-angle, achieving accurate 3D refractive index mapping and the simplest optical setup, simultaneously. Proof of concept experiments were performed successfully on human breast adenocarcinoma MCF-7 cells, opening the way for the full characterization of circulating tumor cells (CTCs) in the new paradigm of liquid biopsy.