Microscopy is used to image in 3D, but is two-dimensional in its roots: the job of the instrument is to focus light from the sample onto a (flat) camera plane, and the depth-of-field for high-resolution microscopy is less than a micrometer, so thick samples simply cannot be imaged in one snapshot. Z-stacking or other techniques such as light-sheet-, confocal-, multiphoton-, and single-molecule-localisation microscopy, record 3D information, but are based on time-scanning and therefore fundamentally incapable of snapshot or video-rate imaging, required to image transients or moving samples. Further, a major obstacle to in-tissue imaging is light scattering. Advanced microscopy techniques aim at suppressing its effects to extract useful sample information. The talk will discuss Computational Imaging techniques to provide high-resolution, time-resolved, depth-extended and three-dimensional microscopy. By definition, extending the depth-of-field voids any optical sectioning capability, and so image recovery assumes samples are sparse in their volume, such as membrane-like surfaces in biological samples or 3D profiling in industrial inspection. Further sparsity is found on imaging point-like sources, such as in particle tracking or single-molecule-localisation microscopy. Application of extended-range 3D microscopy into these areas will be discussed, to enable 3D particle tracking over large volumes and super-resolution microscopy through thick samples. The talk will further discuss how light scattering affects images, looking at retinal tissue as an example, where controlling scattered light enables to extract information; and how simulation tools such as Monte-Carlo modelling of optical systems involving turbid media enable optimisation of computational imaging solutions for in-tissue imaging.

Dr. Guillem Carles obtained a BSc and MSc in Physics at the University of Barcelona, MSc in Computer Vision and Artificial Intelligence at the University Autonomous of Barcelona, and PhD in Physics on Computational Imaging at University of Barcelona in 2011. He moved to University of Glasgow in 2012 and conducted research in various aspects in Computational Imaging. His research includes multi-camera super-resolution imaging in the visible and infrared, foveated multi-aperture optics, computational imaging for retinal screening, Monte-Carlo modelling of light propagation in turbid media, computational imaging for extended-range 3D microscopy, and 3D particle tracking and super-resolution microscopy. He is currently a Leverhulme Trust Early Career fellow.

In this seminar, I will present a revolutionary laser nanofabrication process based on two-photon polymerization (TPP) and an ultrafast random-access digital micromirror device (DMD) scanner. By exploiting binary holography, the DMD scanner can simultaneously generate and control one to tens of foci from a femtosecond laser for parallel nanofabrication; the trajectory of each laser focus can be arbitrarily planned and updated at the DMD pattern rate, i.e., 22.7 kHz. As the control of focus position and laser dosage is entirely discretized, the multi-point DMD scanner can fabricate micro-/nano-structures with substantially improved throughput, grayscale control, precision, and repeatability. Single- and multi-focus laser scanning experiments will be performed to fabricate complex 3-D trusses and woodpile structures, showing a resolution of ~500 nm. The nanofabrication system may be used for largescale nano-prototyping or creation of complex structures, e.g., overhanging structures, that cannot be easily fabricated via conventional raster-scanning-based systems, bringing significant impact to the world of nanomanufacturing.

Prof. Shih-Chi Chen received his B.S. degree in Mechanical Engineering from the National Tsing Hua University, Taiwan, in 1999. He received his S.M. and Ph.D. degrees in Mechanical Engineering from the Massachusetts Institute of Technology, Cambridge, in 2003 and 2007, respectively. Following his graduate work, he entered a post-doctoral fellowship in the Wellman Center for Photomedicine, Harvard Medical School, where his research focused on biomedical optics and endomicroscopy. From 2009 to 2011, he was a Senior Scientist at Nano Terra, Inc., a start-up company founded by Prof. George Whitesides at Harvard University, to develop precision instruments for novel nanofabrication processes. Joining since 2011, he is presently an Associate Professor in the Department of Mechanical and Automation Engineering at the Chinese University of Hong Kong. His current research interests include ultrafast laser applications, biomedical optics, precision engineering, and nanomanufacturing. Prof. Chen is a member of the American Society for Precision Engineering (ASPE), American Society of Mechanical Engineers (ASME), SPIE, The Optical Society (OSA), and Institute of Electrical and Electronics Engineers (IEEE). He received the prestigious R&D 100 Award in 2003 and 2018 for developing a six-axis nanopositioner and an ultrafast nanoscale 3-D printer respectively. In 2013, he received the Early Career Award from University Grants Committee of Hong Kong.

With the progress of biomedical studies, people desire for utilizing different approaches to investigate a biological system, providing multi-dimensional information on a sample. Aiming to this, we integrate phase and fluorescence imaging modalities, as well as fluorescence correlation spectroscopy (FCS), in a confocal laser scanning microscopy (CLSM) system. To perform phase imaging, the depth of field (DOF) of the CLSM system was extended by using a tunable acoustic gradient index of refraction (TAG) lens. A few intensity images of a sample at different defocusing distances were recorded under transmitted illumination, and a quantitative phase image was reconstructed from these intensity images. For the fluorescence imaging, the sample was scanned in 3D, providing a 3D, sectioned fluorescence image of targeted structures. The obtained phase/fluorescence images with pixel-to-pixel correspondence reveal for the same sample complementary information (structural/functional). Moreover, FCS was performed on the same sample to screen the dynamics of fluorescently labeled biomolecules. It was realized by recording intensity traces when the fluorescently labeled biomolecules diffuse through the focus volume of the CLSM system. The auto/cross-correlations of the intensity traces reveal the concentration, hydrodynamic radius, fluorescence kinetics of the investigated molecules, and their interactions. The multimodality imaging/spectroscopy platform was tested on live HeLa cells, of which the membranes were coated with fluorescent cell masks. The combination of the phase/fluorescence imaging enables standalone determination of the refractive index of live cells; the results from FCS characterizes the fluidity of the membranes. The obtained multi-dimensional information is potentially useful in disease diagnosis.

Peng Gao, Ph. D, Professor at Xidian University. He studied Physics and received his Ph.D at the Xi‘an Institute of Optics and Precision Mechanics (XIOPM) in 2011. He was a “Humboldt Fellow” in University Stuttgart (2012-2014) and later Marie-Curie Fellow (IEF) in KIT/University Manchester. He is currently appointed as a full professor at Xidian University and leads a biological imaging and spectroscopy group there, funded by the “Ten-thousand talents program”. The main research lines include but not limited to: (a) phase microscopy in term of digital holographic microscopy (DHM) and reference-less phase retrieval; (b) Super-resolution microscopy and correlation spectroscopy. He had authored around 50 peer-review papers, including Nature Photonics, Advance of Optics and Photonics, and Optics Letters. Some of their works were highlighted by “Nature Methods”, “IOP selection”, “Spotlight on Optics”, and international media such as Science Daily, Physics News, Advance of Engineering

I introduce a newly developed technology known as “Image-Activated Cell Sorting” [Cell 175, 266 (2018)] that realizes real-time image-based intelligent cell sorting at an unprecedented rate. It integrates high-throughput cell microscopy, focusing, sorting, and deep learning on a hybrid software-hardware data-management infrastructure, enabling real-time automated operation for data acquisition, data processing, intelligent decision-making, and actuation. I also show the broad utility of the technology to real-time image-activated sorting of microalgal and blood cells for studying photosynthesis and atherothrombosis, respectively. The technology is highly versatile and expected to enable machine-based scientific discovery in biological, pharmaceutical, and medical sciences.

Keisuke Goda is a professor of chemistry at the University of Tokyo. He obtained a BA degree from UC Berkeley summa cum laude in 2001 and a PhD from MIT in 2007, both in physics. At MIT, he worked on the development of gravitational-wave detectors in the LIGO group which led to the 2017 Nobel Prize in physics. After several years of work on high-speed imaging and microfluidics at Caltech and UCLA, he joined the University of Tokyo as a professor. His research group focuses on the development of serendipity-enabling technologies based on molecular imaging and spectroscopy together with microfluidics and computational analytics. His pioneering work has been published in a number of top journals such as Nature and Cell. He has received numerous honors and prizes including Japan Academy Medal, Yomiuri Gold Medal, and JSPS Prize.

Recently, much effort has been made toward achieving clear and vivid images with natural colors for high-performance displays. Particularly, quantum dots (QDs) have attracted great attention for next-generation displays due to the tuning capability of the emission wavelength, the narrow full width at half maximum (FWHM), and the high quantum efficiency. The narrow FWHM provides the high color purity and the wide color gamut generated by three primary colors of red, green, and blue. For photoluminescence-based QD displays, as one of the critical prerequisites, the uniform dispersion of the QDs without the aggregates and void sites in the light emission layer is most challenging. Another important issue is to harvest the light, emitted from the QDs, in the light propagation along the viewing direction. Together with the development of current emissive displays including organic light-emission diodes and transistors, the evolution of the QD-based displays and the technical issues for commercialization are discussed.

Sin-Doo Lee is a professor of School of Electrical Engineering of Seoul National University, Korea. He received his BS and MS degrees in solid-state physics from Seoul National University, Korea in 1980 and 1982, respectively, and his Ph.D. degree in liquid crystal physics from Brandeis University, USA in 1988. Prof. Lee is one of the leading interdisciplinary scientists with worldwide high reputation in physics, optics, and device engineering of soft matters including liquid crystals, organic semiconductors, and polymers. He has authored about 330 scientific publications and delivered over 340 conference presentations. He is currently the Fellows of three major display societies of SID, SPIE, and OSA. He has been served as the general chair/co-chair, the organizing committee chair, the honors/awards committee chair, and the scientific/technical program committee member in many professional societies. His current research areas include organic nano-electronics, organic field-effect transistors and light-emitting transistors, quantum dot-based emissive displays, autostereoscopic displays, and wearable devices such as energy harvesting and biosensing.

Recently, imaging flow cytometry has been proven advantageous over conventional non-imaging methods in terms of information content for its capability of providing single-cell images, from which, multidimensional biomedical information can be extracted via digital image processing. Those phenotypic variations observed from the cellular images are found to be connected with cellular action mechanisms, which can be used in various field, such as hematology, pharmacology and immunology. However, the throughput of currently available imaging flow cytometry is severely limited to about 1,000 cells/s by the performance of the imaging techniques applied, namely, the shutter speed and frame rate of CCD or CMOS imaging sensors, which hinders its application in large-scale single-cell analysis.
Time-stretch imaging breaks through the speed limitation of CCD and CMOS sensors by applying optical shutter and single-pixel detection. When combined with microfluidic technique, time-stretch imaging is able to achieve high-quality and high-speed image acquisition with a spatial resolution of 780 µm and throughput exceeding 1,000,000 cells/s, respectively, which means similar image quality but 2-3 orders of magnitude higher throughput compared with conventional imaging flow cytometry. In addition, by virtue of machine learning technique, numerous subtle cellular features can be extracted from single-cell images and then accurately analyzed to evaluate cellular action mechanisms. Here we present recent advances and trends of time-stretch imaging in the applications of biomedical research and treatment, such as drug responses detection of cancer cell and evaluation of thrombotic disorders.

Cheng Lei is a Professor in The Institute of Technological Sciences, Wuhan University. He obtained his B.E. degree from Huazhong University of Science and Technology in 2008 and his Ph.D. from Tsinghua University in 2013, both in electronic engineering. In 2018, he joined Wuhan University as a professor. His research interests include ultrafast optical imaging, imaging flow cytometry, artificial intelligence, fiber optics, etc.

Recently, metasurfaces arrested considerable research interest owing to its strong capability in manipulate the light within an ultrathin flat device, which possibly promises tremendous applications in state-of-art optical instruments and technology. Although there have been a lot of advantages based on such subwavelength design, metasurfaces still suffer from several important flaws compared with conventional optical elements, e.g., the working efficiency, working bandwidth, chromatic aberration, and so on. Among these, the uniqueness and necessity of the ultrathin flat platform of metasurface are always questioned if it only works together with other optical elements in a conventional scheme. Here, I would first introduce our recent progresses in chromatic dispersion engineering in metalens, which were developed for achromatic focusing and imaging, depth-of-field (DOF) imaging by metalens array, and spectra-tuned chromatic metalens. Moreover, aiming to achieve the integrated imaging function, we are approaching for a direct integration of the ultrathin metalens and lens array to a camera, where the imaging aberration, chromaticity, image merging, field of view (FOV), and resolution will be discussed. We expect our efforts and approaches will be helpful to develop real unique and applicable meta-photonic devices.

Tao LI (李涛), received his PhD degree in Physics in NJU, 2005. He joined CEAS of NJU in 2008, and was promoted to full professor in Dec. 2013. He was selected to "Dengfeng Talent Program B" of NJU in 2012, and won the "National Funds for Outstanding Young Scientists" and "K.C. Wong Education Foundation" in 2013, award "Person of Year 2017" by Scientific Chinese and "Young and middle-aged leading scientists, engineers and innovators" by MOST in 2018. He is specialized in research of micro-nano photonics, plasmonics, and metamaterials. Up to date, he has published more than 80 peer-reviewed journal papers (including Nature Nanotech., Nature Comm., Phys. Rev. Lett., Nano Lett., Light Sci. Appl., Laser Photon. Rev., etc), which received more than 2500 citations with a current H-index of 28 (Web of Science).

Direct imaging of transient events can greatly aid the understanding of many underlying principles in materials science, chemistry, and biology. These events, often probabilistic and occurring at sub-nanosecond time scales, require real-time imaging at ultra-high temporal resolutions. However, established ultrafast imaging methods fall short due to their requirement for repetitive measurements. To overcome these limitations, we have developed compressed ultrafast photography (CUP)—the world's fastest imaging technology with an imaging speed of up to 10 trillion frames per second [Light Science & Applications 7 42 (2018)]. CUP has made first-ever real-time recording of a number of optical phenomena, including faster-than-light propagation of non-information, laser-pumped fluorescence emission [Nature 516 74-77 (2014)], time-resolved light backscattering [Scientific Reports 5 15504 (2015)], and propagating photonic Mach cones [Science Advances 3 e1601814 (2017)]. Recently, the concept of CUP has been implemented in transmission electron microscopy [Micron 117 47 (2019)] and standard CMOS cameras [Optics Letters 44 1387 (2019)]. Given CUP's passive, ultrafast, and real-time imaging capability, we envision it to facilitate widespread applications in both fundamental and applied sciences.

Dr. Jinyang Liang is currently an Assistant Professor at the Institut National de la Recherche Scientifique (INRS) - Université du Québec. His research interests cover a broad range of areas, including ultrafast imaging, photoacoustic microscopy, wavefront engineering, and high-precision laser beam shaping. His research primarily focuses on implementing optical modulation techniques to develop new optical instruments for applications in physics and biology. He has published over 50 journal papers and conference proceedings, including Nature (cover story), Science Advances, and Light: Science & Applications. He holds two U.S. patents on ultrafast optical imaging technology. He received his B.E. degree in Optoelectronic Engineering from Beijing Institute of Technology in 2007, and his M.S. and Ph.D. degrees in Electrical Engineering from the University of Texas at Austin, in 2009 and 2012. From 2012 to 2017, he was a postdoctoral trainee in Washington University in St. Louis and California Institute of Technology.

The biggest challenge on the path towards bio-imaging is obtaining spatial and spectral information of a volumetric sample in real-time. Advances in this field are of vital importance for biology, material sciences, and medical applications. For example, cancer is one of the leading causes of death in the world, thus gaining a mechanistic understanding of cancer cell processes will significantly impact therapies targeting cancer metastasis pathways. Revealing the entire process with its surrounding environment will require real-time HD imaging systems that will open the way for better understanding of cancer onset and tissue morphology. This talk will introduce real-time 3D volume holographic imaging systems, which are based on multiplexed volume holographic gratings acting as spatial-spectral filters used in conventional optical imaging systems. This allows the acquisition of spatial images with spectral selectivity but without scanning in both transverse and longitudinal directions. In addition, with proper multiplexed holographic pupil engineering, the volume holographic imaging systems can provide multiple depth-resolved phase-contrast imaging in real time and quantitative phase imaging in a single shot. Furthermore, the talk will address volume holographic techniques incorporating other state-of-the-art methods to better manipulate light for imaging as well as illumination.

Yuan Luo received the MSc and PhD degrees in College of Optical Sciences in 2007 and 2008, respectively, from the University of Arizona. After post-doctoral work at Massachusetts Institute of Technology (MIT, 2009-2011), he joined the faculty at National Taiwan University (NTU) in 2011, where he is now Associate Professor of Institute of Medical Device and Imaging, and holds the Associate Professorship in NTU Molecular Imaging Center, as well as NTU YoungLin Institute of Health. He has worked or held visiting appointments at the Singapore-MIT Alliance for Research and Technology (SMART) Centre in Singapore. His research interests are three-dimensional (3D) and spectral imaging; shift-invariant optics theory and implementation with 3D active structured light. He is member of the Optical Society of America (OSA), and International Society for Optical Engineering (SPIE).

Ultracold atomic Bose-Einstein condensates (BECs) are one of the most isolated and controllable systems for the investigation of diverse quantum superfluid phenomena. These features are provided by the BEC's isolation inside an ultrahigh vacuum chamber, along with externally defined and controlled trapping potentials. Optical dipole traps provide the best means for trapping and microscopically patterning and manipulating these superfluid systems within the vacuum chamber. In my talk, I will describe our approach that uses direct imaging of a digital micromirror array (DMD) for the production of arbitrary and dynamic optical traps for BECs. These traps allow for the generation of configurable and homogenous BECs, and enable new types of nonequilibrium superfluid experiments in quasi-2D. In addition to the hard-walled potentials produced by the binary DMD device, I will describe our approach of using halftone DMD patterns for achieving smooth optical potentials. Our method utilises image-recognition and normalisation of the measured BEC density, for comparison with a target image. Using this data, we implement feedforward correction of the optical trap. In the second part of my talk, I will describe how these techniques have enabled diverse studies of quantum turbulence and other superfluid phenomena in our laboratory, including the first observations of high-energy vortex clusters in a quantum fluid.

Dr Tyler Neely joined the ARC Centre of Excellence for Engineered Quantum Systems at the University of Queensland (UQ) in 2012. He began construction on a new BEC apparatus aimed at novel optical trapping for BECs, with the aim of studying superfluid phenomena and superfluid transport. Prior to UQ, he completed a postdoc at the National Institute of Standards and Technology (NIST) in Boulder, CO, USA, where he developed mid-infrared femtosecond lasers for molecular spectroscopy. He obtained his PhD in Optical Sciences at the University of Arizona in 2010.

Fringe projection prolilometry is important for 3D shape measurement (3D imaging). In this paper, we introduce an interesting special gray-code to reduce the number of fringe patterns to be projected and thus achieve higher-speed data acquisition. First, through a weighted optimization algorithm, special binary code patterns are designed. These patterns will be projected and defocused into special ternary or quaternary gray codes, which are more expressive for information coding. Second, these codes will be expectedly distorted due to the object shape, but also undesirably distorted due to the imperfect experimental condition such as non-uniform object surface property and ambient light. A normalization-denoising-clustering process is then used to recover the ideal gray codes for successful phase unwrapping. Finally, continuity/geometry constraints are integrated with this phase unwrapping method to further reduce the number of required patterns. As a result, a high-quality 3D shape can be reconstructed by only five binary patterns effectively and efficiently.

Dr Qian Kemao is an Associate Professor in the School of Computer Science and Engineering (SCSE) at Nanyang Technological University (NTU). He graduated from University of Science and Technology of China (USTC), where he got his BE, ME and PhD degrees. His research interests include optical metrology, image processing, parallel computing, and computer vision.

Focusing light through and within scattering media is critically important in many applications, such as high-resolution optical imaging, photodynamic therapy, and optical manipulation. However, in scattering media such as biological tissue, light gradually loses the memory of its initial propagation direction, which makes it difficult to create a focus beyond the optical diffusion limit (~1 mm deep). To break this limit, wavefront shaping has been developed with the capability of focusing light through and inside scattering media. Based on the time-reversal principle, this technique first measures the scattered wavefront through holography, and then compensates the wavefront distortion using a spatial light modulator. In this talk, I will present some of the most recently achieved results, including extending the limit of focusing depth by more than an order of magnitude and implementing a new high speed wavefront shaping scheme. These works show the promise of time-reversal based wavefront shaping techniques to revolutionize biomedicine with deep-tissue noninvasive optical imaging, manipulation, and therapy.

Dr. Yuecheng Shen received his BSc in applied physics from the University of Science and Technology of China (2010) and his Ph.D. in electrical engineering from Washington University in St. Louis (2015). He then did his postdoc research under the tutelage of Dr. Lihong V. Wang at California Institute of Technology. He is now an associate professor in the school of electronics and information technology at Sun Yat-sen University.
Dr. Shen's research interests focus on developing wavefront shaping technologies, which overcome optical scattering effects and enable deep tissue noninvasive optical imaging, optogenetics, optical tweezing, and phototherapy. He has published more than 30 articles in peer-reviewed journals (including physical Review Letter and Optica) and has 10 U.S. patents/provisional patents.

Driven by the challenges in biological and clinical research to visualize living cells and organisms at different imaging scale in both time (from sub-millisecond dynamics to hours-to-days evolution) and space (from single-cell to whole organism level), we recently developed a new type of high-speed all-optical laser-scanning technique, called free-space angular-chirp-enhanced delay (FACED). This technique allows us to transform the static laser beam into an ultrafast line-scanning beam using an almost-parallel mirror pair, resembling the concept of “infinity mirror”. We have employed FACED imaging to enable ultrahigh throughput microfluidic single-cell imaging with multiple image contrasts, ranging from quantitative phase and fluorescence, and multi-photon contrasts (e.g. two-photon fluorescence, second harmonic generation) at a line-scan rate beyond 10's MHz (i.e. an imaging throughput up to ~100,000 cells/sec). This empowers new generation of deep image-based single-cell analysis. Using an ultrafast two-photon fluorescence microscope enabled by FACED, we also demonstrate neural activity imaging in vivo at 1,000 frames per second and submicron spatial resolution. This ultrafast imaging method enabled monitoring of electrical activity down to 300 μm below the brain surface in head fixed awake mice. Furthermore, using the concept of FACED combined with multiplexed plane-wide encoding, we demonstrate a new type of scanless volumetric imaging technique that exploits a parallelized 3D light-sheet fluorescence imaging strategy. It bypasses the widely adopted coherent multi-light-sheet generation concept and its complication in precise phase control and mechanical scanning/dithering for volumetric imaging. Not only can such this 3D imaging technique maximize spatial duty-cycle and signal-to-noise ratio, but also can outperform the majority of the scanning-based 3D imaging modalities in further reduction in photobleaching. This would be well-suited for long-term dynamical volumetric live cellular, tissue, and organism imaging, as well as high-throughput volumetric visualization for 3D histopathological investigation of archival biological samples.

Kevin Tsia received his Ph.D. degree at the Electrical Engineering Department, at University of California, Los Angeles (UCLA), in 2009. He is currently an Associate Professor in the Department of Electrical and Electronic Engineering, and the Program Director of the Biomedical Engineering Program, at the University of Hong Kong. His research interest covers a broad range of subject matters, including ultra-fast optical imaging for imaging flow cytometry and cell-based assay; high-speed in-vivo brain imaging; computational approaches for single-cell analysis. His pervious researches, such as the World's fastest optical imaging system, have attracted worldwide press coverage and featured in many science and technology review magazines such as MIT Technology Review, EE Times and Science News. He received Early Career Award 2012-2013 by the Research Grants Council (RGC) in Hong Kong. He also received the Outstanding Young Research Award 2015 at HKU as well as 14th Chinese Science and Technology Award for Young Scientists in 2016. His recent research on ultrafast optofluidic imaging technologies, dubbed “ATOM” and “FACED”, have also been covered by media and scientific magazines. He is author or coauthor of over 160 journal publications, conference papers and book chapters. He holds 3 granted and 4 pending US patents on ultrafast optical imaging technologies. He is a co-founder of start-up company commercializing the high-speed microscopy technology for clinical diagnostic applications.

An adaptive optics (AO) assisted 4Pi single molecule switching (SMS) microscope for ultra-high spatial resolution single molecule imaging will be present.
Super-resolution microscopes provide nanometer spatial resolution for cell biological studies; however, the axial resolution of standard SMS microscopes is inferior to the transverse resolution. By using two opposing objective lenses for coherent detection of fluorescent emission, a SMS microscope in 4Pi configuration enables ultra-high axial resolution with an improved signal collection efficiency. Due to the nature of 4Pi imaging, even a moderate sample thickness will inevitably introduce aberrations that affect the focusing performance of the system. More importantly, the aberrations experienced by the two arms of the 4Pi cavity are different and will vary differently as the imaging position moves axially. For these reasons, the axial resolution and imaging efficiency deteriorate quickly with depth in thick samples. This limits the axial imaging range and makes imaging large cells with uncompromised resolution impossible without compensating the depth dependent aberrations.
The nature of aberrations in a 4Pi cavity has been described and the effect on the system performance was studied. Based on this knowledge, we demonstrate aberration correction methods using a novel sensorless AO approach. Two deformable mirrors (DM) are employed in the microscope, one for each objective. A compact interferometer is devised for accurate DM calibration and control, and we estimate the aberrations base on imaging metrics. The AO 4Pi SMS microscope is tested in imaging whole biological cells, and it allow a significant larger axial imaging range.

Jingyu Wang, from a Biomedical engineering background, obtained his PhD From Prof. Adrian Podoleanu's group, University of Kent, working on parallel detection Optical coherence tomography. After that, he switched to the fields of microscopy methods. He built a six-color single molecule fluorescence microscope for DNA repair study in Dr. Neil Kad's group, in University of Kent. Jingyu joined Prof. Martin Booth's Dynamic Optics and Photonics group in University Oxford in 2017 as a Post-doctoral Research Scientist. He has been working on applying adaptive optics methods on various microscopes, including 2-photon microscope, Third-Harmonic microscope, light sheet microscope and single molecule localization super-resolution microscope. He recently works on developing a novel adaptive optics method on a 4Pi single molecule switching microscope, with collaboration with Joerg Bewersdorf's group (Yale, U.S.), Jonas Ries group (EMBL, Germany) and St Johnston's Group, Cambridge (U.K.).

The 2014 Nobel Prize in Chemistry is an award to praise the development of super-resolution microscopy, which has pushed the fluorescence microscopy to a new summit. However, there still exist challenges for further application of super-resolution: (1) Better spatial resolution is always preferred especially at no additional cost; (2) Deeper imaging depth inside the scattering specimen; and (3) Richer biological information.
I will introduce three technologies we developed recently for these aims. Firstly, with mirror-enhanced super-resolution, we are able to convert a STED system to a STED-4Pi, with ~4x STED intensity and ~2-fold of resolution, with the same STED power (MEANS-STED). Secondly, benefitted from the rich choice of energy levels of upconversion nanoparticles, we have achieved 28 nm resolution with intermediate state STED, with only 30mW CW laser power. Further, by modulating the STED beam as Bessel beam while maintaining the excitation beam as Gaussian, we have achieved 155 um deep STED imaging (GB-STED). Thirdly, we have also achieved a new super-resolution technique through the demodulation of fluorescent dipole orientation (SDOM). The dipole orientation describes the underlying structures it attaches to. A series of biological structures can be revealed by SDOM, but not conventional polarization microscopy.

Dr. Peng Xi is an associate professor in College of Engineering, Peking University, China. His current research interests are focused on research and development of optical super-resolution microscopy techniques. He has published over 60 scientific papers in peer-reviewed journals including Nature, and holds 10 issued invention patents, including 3 US patents. He is elected as a senior member of OSA since 2015. He has been awarded the Beijing Distinguished Young Scholar by Beijing Natural Science Foundation in 2018. He is on the editorial board of 5 SCI-indexed journals: Light: Science and Applications, Advanced Photonics, Scientific Reports, Microscopy Research and Techniques, and Micron. His research is sponsored by the National Science Foundation of China, and Ministry of Science and Technology in China. He has been invited to give many invited talks in international conferences hosted by OSA and SPIE.

We appear opaque because our tissues scatter light very strongly. Traditionally, optical imaging and the focusing of light in biological tissues is confounded by the extreme scattering nature of tissues. Interestingly, optical scattering is time-symmetric and we can exploit optical phase conjugation methods to reverse scattering effects. Over the past decade, my team has worked on wavefront control technologies to meaningfully focus light through living tissues for imaging and optogenetic stimulation purposes. I will report on our recent experimental findings. In addition, I will also talk about how the interplay between scattering and wavefront control is rich and tangled, with surprising optical opportunities waiting to be uncovered. For example, the incorporation of scattering within an optical system can actually improve system performance – a cloudy piece of plastic can actually be a better optical element than a well made lens!

Education
PhD, EECS, MIT, 2002
BSc, Mathematics, MIT, 2002
MEng, EECS, MIT, 1997
BSc, Physics, MIT, 1997
BSc, EECS, MIT, 1997
Field of Study
Professor Yang's research efforts are in the areas of novel microscopy development and time-reversal based optical focusing. Prof. Yang joined the California Institute of Technology in 2003. He is a professor in the areas of Electrical Engineering, Bioengineering and Medical Engineering. He has received the NSF Career Award, the Coulter Foundation Early Career Phase I and II Awards, and the NIH Director's New Innovator Award. In 2008 he was named one of Discover Magazine's ‘20 Best Brains Under 40'. He is a Coulter Fellow, an AIMBE Fellow and an OSA Fellow.
His research efforts can be categorized into two major groups – high throughput microscopy development and time-reversal based optical focusing.

Metasurfaces can provide great flexibility to shape the wavefront of light with a spatial resolution at the sub-wavelength level, which opens up new avenues for many applications including, but not limited to, imaging, display, and holography. One application we are particularly interested in is depth sensing. Sensing 3D (depth) information can enable facial and object recognition, and can be of vital importance in augmented reality, robotics, autonomous driving, and a wide range of other applications. Metasurfaces can play unique roles in both types of mainstream depth sensing approaches, namely structured light, and time-of-flight. In this talk, I will share our preliminary results on how metasurfaces can be used to generate structured light pattern with extremely high efficiency, high uniformity, and large field of view. I will also discuss the opportunities and challenges of using metasurfaces for electro-optical beam steering, towards the realization of integrated 3D sensing, imaging, and display systems.

Yuanmu Yang (杨原牧) is an Associate Professor at the Department of Precision Instrument, Tsinghua University. He received his PhD degree in Interdisciplinary Materials Science from Vanderbilt University in 2015. From 2015 to 2017, he was a postdoctoral appointee at Sandia National Laboratories. From 2017 to 2018, he was a metamaterials scientist at Intellectual Ventures, and participated in the foundation of Lumotive Inc., the world's first solid-state lidar company based on the metasurface technology. He has co-authored more than 15 scientific contributions published in peer-reviewed journals including Nature Photonics, Nature Physics, Nature Communications, and Nano Letters, receiving over 2000 citations. His research interests include nanophotonics, metamaterials, and nonlinear optics.

Geometric metasurface (GEMS) that consists of an array of metal or dielectric nanobricks with spatially varying orientations, has shown continuous and accurate phase control of light with limited losses, representing a new model for the design of high performance optical elements and devices such as holograms. In this presentation, we show the design and experiments of various meta-holograms developed in our group, including metal-insulator-metal (MIM) based hologram with efficiency as high as 80% and broadband response (600-1100 nm), dielectric Fourier and image holograms with aspect ratio as low as 1.5, and transflective meta-holograms which can generate holographic image filling the full 4π Space. Taking the advantages of ultracompactness, continuous phase modulation, flexible design and ease of fabrication, GEMS based holograms could be utilized for various applications including anticounterfeiting, optical information encryption and decryption, compact display and optical storage, etc.

Guoxing Zheng is a professor at the Electronic Information School, Wuhan University. He received his Ph. D from the Institute of Optics and Electronics, Chinese Academy of Sciences in 2005. From 2014 to 2015, he was a visiting scholar at the University of Birmingham, UK. Dr Zheng's current research focuses on metamaterials (metasurfaces) and their applications in scientific research and industry. He has published over 30 inventive patents and more than 50 research papers in optical related fields including Nature Nanotechnology, Nature Communications, Science Advances, Light: Science & Applications, ACS Nano, Scientific Reports, Optics Letters, and Optics Express, etc. Dr Zheng has undertaken more than 10 research projects including 4 funds from NSFC and one Hubei Provincial Funds for Distinguished Young Scientists. Currently, he is an executive member of the Hubei Optical Society, editorial committee member of Journal of Applied Optics (in Chinese) and senior member of the Chinese Optical Society, etc.

Quantitative phase microscopy (QPM) is a label-free imaging technique that has been widely applied to biological imaging and material metrology. Our lab has recently empowered QPM with artificial intelligence (AI) and ultra-high 3D imaging capability to address cutting-edge applications. In the first development, we have integrated artificial neural networks into a QPM system for human white blood cell (WBC) classification. Our QPM can automatically classify healthy human WBC subtypes with 90% accuracy, similarly or better than current standard methods. In the second development, we have implemented high speed digital micro-mirror devices (DMDs) and a high-speed image sensor for achieving phase imaging at > 10,000 fps. This system has been further advanced to achieve 3D phase imaging of transparent structures with ~200 nm lateral resolution and ~ 400 nm axial resolution at > 100 fps speed. We will present our current progresses on using such high-speed system for biomedical imaging and material metrology applications.

Dr. Renjie Zhou is an Assistant Professor in the Department of Biomedical Engineering at The Chinese University of Hong Kong. He directs the Laser Metrology and Biomedicine Laboratory. Dr. Zhou received his doctoral degree in Electrical and Computer Engineering from the University of Illinois at Urbana-Champaign in 2014 and took a postdoc training at the George R. Harrison Spectroscopy Lab at MIT. His current research interest is in developing optical based technologies for material metrology and biomedical imaging applications. He has co-authored > 50 journal and conference papers.

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