This PDF file contains the front matter associated with SPIE Proceedings Volume 11925, including the Title Page, Copyright information, and Table of Contents.

Fluorescence polarization microscopy plays a vital role in studying molecular structures and dynamics of biocomplexes by imaging both the intensity and orientation of fluorescent dipoles. Super-resolution (SR) microscopy provides the ultrastructure of subcellular organelles, yet conventional SR lacks the dipole orientation information. We developed polarized structured illumination microscopy (pSIM) to achieve fluorescence super-resolution polarization microscopy.

Laser ablation has come an alternative solution for tumor treatment, and it can be used to remove or shrink tumor tissue. In the previous reports, the pulsed lasers are the most common laser as the light source of laser treatment due to the controllable thermal damage, but it is difficult to use continuous-wave (CW) lasers for tissue ablation because of unpredictable laser damage and thermal effect. Typically, the CW lasers are cost effective in comparison to the pulsed lasers. Additionally, it is also challenging to accurately identify the tumor region for laser therapy to avoid the extra damage on the surrounding tissue. To overcome the limitation of using CW lasers for tumor therapy and to identify the tumor region for laser therapy, an imaging method to monitor the thermal effect induced by the CW laser in real time and to distinguish the tumor region is required. In this study, we develop an optical coherence tomography (OCT)/optical coherence angiography (OCA)-guided laser treatment system with a CW laser diode which is significantly much cheaper than pulsed lasers. To investigate the laser-induced thermal damage, a method based on the analysis of the OCT backscattered intensity is proposed. Moreover, the thermal effect on the vessels of skin is also quantitatively investigated. However, to accurately identify the tumor region, OCT and OCA results could be effective indicators according to the difference of normal and tumor tissue in the backscattered intensity and the vascular distribution. The automatic and objective identification of tumor region can be achieved based on deep learning, enabling to discriminate the tumor tissue with a high sensitivity of 97 %. Finally, the integrated system and the proposed method are implemented for the treatment of skin tumor on the mouse model. The results illustrate that the OCT/OCA-guided laser ablation system can accurately and effectively remove tumor tissues with controllable photodamage. Moreover, the system cost may be significantly reduced by using the continuous wave laser diode.

Since the days of Cajal, optical microscopy has been a vital tool for physiology, and neuroscientists have accumulated significant amount of information on structures and functions of isolated neurons. However, to understand the emergent properties of a brain, functional observation of complicated neuronal networks is necessary, leading to the request of volumetric imaging with high speed, deep penetration, and sub-cellular resolution. In this talk, I report our recent advances on pushing the speed of volumetric imaging, and its applications on Drosophila and mouse brains.

Since the days of Cajal, optical microscopy has been a vital tool for physiology, and neuroscientists have accumulated significant amount of information on structures and functions of isolated neurons. However, to understand the emergent properties of a brain, functional observation of complicated neuronal networks is necessary, leading to the request of volumetric imaging with high speed, deep penetration, and sub-cellular resolution. In this talk, I report our recent advances on pushing the speed of volumetric imaging, and its applications on Drosophila and mouse brains.

We recently found that massive but transient DNA strand breaks, a kind of DNA damage, can trigger cellular reprogramming of differentiated cells to stem cells in the moss Physcomitrella patens (Physcomitrella). In Physcomitrella, DNA is massively damaged by the treatment with a DNA strand break-inducing reagent at high concentration. The DNA damage was repaired within 24 hours after the removal of the reagent. Then, the promoter activity of STEMIN1, encoding an integrator of the reprogramming signals, became active in a part of leaf cells, which eventually became stem cells. Levels of DNA strand breaks were quantified by performing comet assay, where the nuclei are subject to electrophoresis, stained with the fluorescent dye that binds to DNA, and observed with fluorescent microscope. The promoter activity of STEMIN1 was visualized using fluorescent protein and observed with fluorescent microscopy.

Focus-shift using rotating planar mirrors for light sheet microscopy

We have developed a stimulation method for a living cell by using electron beam exposure. Liquid water is a major chemical component of a cell and is expected to be decomposed into reactive oxygen species (ROS) upon the beam exposure, which is known as a cellular signaling molecule and modulates various cellular functions. The beam target cell is stained with a fluorescence probe, CM-H2DCFDA which is sensitive to intracellular ROS and emits bright fluorescence once it reacts with ROS. By comparing the fluorescence intensity of the target cell before and after the beam exposure, it is implied that intracellular ROS is generated by electron beam irradiation. Therefore, this method can modulate cellular physiology through artificial generation of ROS, which is applied for future biological researches.

We present a deep ultraviolet (DUV) light microscope capable of serial block-face imaging of the whole rodent brain. The capability of the 3D-DUV microscope for quantitative volumetric analysis of the small substructures of habenula is shown. It is expected that large scale wide-field high resolution analysis of the smaller regions would allow for elucidating the functional changes linked with the morphological changes in brain under pathological conditions.

Combination of infrared laser heating through a microscope optics and heat shock response of cells achieves single-cell gene induction in vivo. We will introduce a live-cell manipulation technique and show representative data in living animals and plants. Further, we will discuss a local heating property in vivo through a temperature imaging technique using a fluorescent thermometer.

The THz/Far-IR Beamline at the Australian Synchrotron was used to demonstrate a novel method of estimating the dielectric properties of water based substances in the 2.0 THz region. The method involves using an ATR apparatus with a diamond crystal in a way that converts the apparatus to a reflection/transmission mode by using a mirror at a set distance from the crystal/sample interface to reflect the transmitted portion of the incoming beam back to the detector. The method can extract the full dielectric properties of a sample. The method is only limited by the frequency range of the source and the sensitivity range of the detector. It is best suited to studies at 2.0 THz and above with a diamond crystal ATR apparatus, since the combination of the refractive index of diamond (n=2.40) and water (n=1.95 at 2.0 THz) are in the optimal ratio to produce excellent contrast. Water and water based gel were used to demonstrate the technique.

We theoretically predict existence of Spoof Zenneck waves supported by a subwavelength corrugated surface in the terahertz spectral range, which corresponds to an alternative to plasmon-polariton for THz sensing application.

Neurons receive synaptic inputs via its dendrites and understanding the processing of those inputs as well as the influence of the dendrite’s non-linear properties are key components to decode the neuron’s computing power. Recent breakthroughs to understand dendritic function make use holographic structured illumination to stimulate and/or record dendritic activity either via photochemical or optogenetic tools. In this talk, I will summarize our efforts where we used holograms to probe the integrative and non-linear properties of dendrites of a neuron. Understanding the role of dendrites in neuronal function offer significant insights as to how these neurons function as tiny computers in the brain.

Currently, in various biological research fields, optical control of cellular responses is widely utilized, leading to establishing a research field named “optogenetics”. Successful optogenetic studies need both state-of-art optical devices illuminating target issues with a high spatiotemporal resolution and optical control tools (typically photosensitive proteins) driving cellular reactions in a light-dependent manner. Most of optogenetic analyses have used channelrhodopsins, lightsensitive ion channels, as control tools. Alternatively, animal opsins, light-sensitive G protein-coupled receptors, can be used as tools to drive a wide variety of G protein-dependent intracellular signaling pathways. Here, I characterize molecular properties of invertebrate opsins by spectroscopic and electrophysiological techniques, and introduce them as “ON-OFF” switch of GPCR signalings. Also, I discuss potentials of the animal opsins as optogenetic tools to expand the research field.

We developed a high-speed planar lightwave circuit digital holographic microscope (PLC-DHM) that used a thin film heater for thermo-optical phase shifter. Owing to the high efficiency of thermo-optical effect of phase shifter in PLC-DHM, a 2π phase modulation was achieved in 2.5 ms. By setting the frame rate of interference fringes acquisition to 100 fps and the phase shift interval to 10 ms, the reconstructed moving images with frame rate of 25 fps was obtained. Moreover, we obtained microscopic moving images of biological samples such as volvox and daphnia.

A new configuration of lensless digital holographic microscope based on a wedge plate is demonstrated. The system is simple in geometry, compact in size and highly stable in temporal phase measurements leading to the accurate investigations of minute membrane fluctuations of the biological cells. The proposed system is used for label-free quantitative phase imaging of the human red blood cells (RBCs) and the investigations of morphology and physiological parameters related to the phase information. The obtained results confirm the feasibility and effectiveness of the proposed system.

We present simultaneous three-dimensional (3D) trajectories of a mother colony and a daughter colony of a Volvox moving in water by a parallel phase-shifting digital holographic microscope. The mother colony was detected as a circle in the reconstructed phase image of the Volvox. While a daughter colony was detected as a circle in the reconstructed amplitude image of the Volvox. The lateral position of each colony was determined as the center of each circle. The depth position of each colony was determined as the position that provided the sharpest reconstructed amplitude image of the edge of each colony during the refocusing of the reconstructed image of the Volvox. We successfully trajected each colony dynamically moving in an area of 0.8 mm × 0.8 mm × 1 mm.

Phase-shifting digital holography has a feature that a hologram can be acquired with a spatial resolution of an image sensor. The interference images should be acquired at multiple times while the phase-shifting is given to the reference light. Therefore, some idea for imaging a moving object have been discussed. The phase-shifting digital holography with burst-imaging method is proposed for imaging a moving object. The phase-shifting digital holography at 460 μs is demonstrated by using a high-speed camera and a high-speed phase modulation based on a piezoelectric element.

Image reconstruction can be formulated by the Fredholm equation of the first kind. The method of projections onto convex sets (POCS) is an iterative algorithm for solving the equation. Multiplicative algebraic reconstruction techniques (MART) is one of POCS for solving a system of simultaneous equation. By discretizing the image reconstruction problem, we applied the MART to the problems and evaluate the image quality in computer simulations. We also investigated the normalized mean square error of reconstructed images with respect to the variations of the number of detectors and views, the relaxation parameters.

Image reconstruction of objects through scattering media is a challenging task. In recent years, deep learning has been used for image reconstruction from scattering images. As described in this paper, we investigated image reconstruction of objects placed between a pair of scattering media by deep learning. Speckle images were captured through a 4-f imaging system. Deep learning can reconstruct object between two diffusers. The influence of diffusion angles of two diffusers on the image reconstruction is investigated.

Lightfield (also known as integral or plenoptic) microscopy has been introduced successfully in 3D bioimaging. The strongest point of this technique when compared with conventional 3D microscopy arquitectures is its capability of capturing the 3D information of the sample in a single-shot manner. Despite this advantage, lightfield microscopy currently faces some challenges, like improving the resolution and depth of field of the reconstructed specimens or the development and optimization of specially-adapted reconstruction algorithms. In this contribution we review a new paradigm, namely, the Fourier lightfield microscope (FLMic), that improves the capabilities of the technique and we present recent advances and applications of this new architecture. As an example, we describe a protocol that takes profit from FLMic concept for providing, in a single-shot, 3D dark-field images of volumetric transparent samples.

Optical coherence tomography (OCT) is a non-invasive cross-sectional imaging technique with micrometer resolution. We have been investigating ultrahigh-resolution (UHR)-OCT using supercontinuum. The characteristics of OCT imaging depend on the optical wavelength used. In order to investigate the wavelength dependence of UHR-OCT, the wideband, high-power, low-noise supercontinua were generated at wavelengths of 0.8, 1.1, 1.3, and 1.7 um based on ultrashort pulses and nonlinear fibers. The wavelength dependence of OCT imaging was examined quantitatively using biological phantoms and rat lung tissue. Then we developed UHR-OCT and optical coherence microscopy (OCM) at 1.7 um, which is called as “Optical Window III”. The high-resolution and high-penetration imaging of mouse brain was demonstrated.

Fast motions of biological molecules, such as lipids and proteins, have been observed with gold nanoparticles that work as contrast agent for optical microscopy. Because of the strong scattering signal of gold nanoparticles, motions of the biomolecules can be investigated with high temporal resolution and spatial precision. To further analyze complex interactions of multiple biological molecules, development of multicolor imaging system with metallic nanoparticles is important. Here, we developed a multicolor imaging system using silver and silver-gold alloy nanoparticles together with gold nanoparticles. We used multiple lasers that matched with plasmon resonance of each metal nanoparticles, and constructed a total internal reflection multicolor dark-field microscope with spectrophotometer. Fast and complex motions of multiple phospholipids in supported membranes, and multiple kinesins were observed at 100 μs time resolution.

Multiplex fluorescence imaging is an important technique for elucidating activities of cells through visualization of the behavior of biomolecules simultaneously. In this paper, we present a method for constructing a fluorescence tag library using Förster resonance energy transfer (FRET) networks and DNA nanostructures which can change in response to molecular input. This method enables us, for example, to detect an event of sensing a target molecule by receiving spectral signals from the FRET network. Calculation results demonstrate that use of DNA nanostructures is effective to switch the fluorescence spectrum generated from a fluorescence tag when sensing a target molecule. The diversity of spectral fingerprints of the tags is also verified. The method has capability in implementing a large sort of fluorescence tags for multiplex imaging.

We propose a novel imaging method using the Ghost Imaging (GI) in a photon limited imaging. In this report, in order to obtain image using few photons, the First Photon-detection Time (FPT) is applied to the GI. The proposed signal detection method is able to obtain a signal with only 1 photon. The FPT has variations that are due to a shot noise. Using a correlation, effect of the noise on images is removed. As a result, the GI with FPT (FPGI) was able to obtain high quality image than a conventional imaging method using same photon number. Furthermore, to improve the detection time, we modified machine learning to reduce the measurement number in the view point of noise influence.

In this paper, we integrate the fluorescence and phase imaging simultaneously that uses the light field and the transport of intensity equation (TIE). Here, the fluorescence information is obtained by the light field imaging with an electrically tunable lens while phase imaging is done by TIE. For fluorescence, different intensity stacks are captured with image sensor to be used for reconstructing the fluorescence images using the concept of light field. To get the phase information of the same sample along with fluorescence, the three intensity images are captured by another image sensor for solving TIE for phase data. Experimental results of micro beads are presented in support of simultaneous imaging technique.

Integration of optical imaging systems with different axial specifications including the maximum measurable range and the axial resolution expands the axial dynamic range. In this research, an optical time-of-flight and an optical coherence tomography were integrated, because both methods have a measurable range that overlaps in the submillimeter range. The integrated optical imaging system has the maximum measurable range of several ten centimeters and the axial resolution of several micrometers, and also get san inside observation ability derived from the feature of the optical coherence tomography

The purpose of the present study was to determine spatiotemporal dynamics of the red blood cell flow in the brain capillaries. To this end, two-photon microscopy was used to concurrently image blood plasma and blood cells expressing fluorescent proteins in the anesthetized rat cortex. Kymographic analysis showed that flow velocity of the red blood cells varied at the bifurcations of brain capillaries, indicating that the bifurcations serve as resistance for the red blood cell flow. Our results further suggest that interactions between the red blood cells and capillary lumen contribute to resistance to capillary flow.

Waterborne microplastics can be difficult to detect in situ. We report on a method of visualizing microplastics using their inherent birefringence. By using a full-Stokes polarization camera for measurement, the microplastics can be visualized and quantified in real-time. In addition, we show that the camera is able to visualize PET microplastics consumed by brine shrimps in vivo.

A bio-optic gas-imaging system (sniff-cam) with enzyme immobilized mesh demonstrates a spatiotemporal gasimaging for human volatiles (i.e., ethanol, acetaldehyde, etc. after drinking). A bio-fluorometric technique was applied to improve the sensitivity of the gas visualization system. The bio-fluorometric sniff-cam for ethanol was constructed with alcohol dehydrogenase (ADH) immobilized mesh and the NADH imaging unit (UV-LED array and highly sensitive CMOS), thus imaging human ethanol in the gas phase not only exhaled air but also transcutaneous vapor after drinking. The sniffer system would be useful for detecting the volatile biomarkers.

In our previous study, we proposed a hand-waving finger vein authentication system, in which finger region extraction from captured images was effective to verify the finger vein patterns with high accuracy. However, it is not easy to extract the correct finger region from grayscale images that are taken with a near infra-red LED, because the background condition of the captured image changes complicatedly according to the location of the waving hand. In order to overcome this limitation, we propose an alternative finger region extraction method that takes color images with an RGB camera and a white light source and identifies the finger region based on the skin color information.

A fracture is the solution of continuity of bone tissue in any bone of the body occurs as a result of excessive stress that exceeds bone resistance, ie is the consequence of a single or multiple overload and occurs in milliseconds. The development of magnetic resonance imaging and computerized tomography have made it possible to know and evaluate the different pathologies of the human being more accurately. Edge detection is a fundamental tool in image medical processing, particularly in the areas of feature detection, which aim at identifying points in a digital image at which the image has discontinuities. In order to improve the computing speed, was used parallel computing which support NVIDIA GPU. This work presents an improved methodology for processing bone fracture images before and after surgery using segmentation and graphic accelerator cards to help the medical specialist in the analysis and evaluation of the images.

Mueller polarization imaging technology can fully reflect the polarization characteristics of the sample, and can be used as a method for imaging thin pathological sections of collagen tissue samples. So far, there has been no actual publication about the detection of transplanted tendons using Mueller matrix imaging technology. In this paper, we apply the Mueller imaging polarimeter for quantitative detection of rabbit transplanted tendon samples with or without tenocytes. The polar decomposition parameters of the Mueller matrix of the rabbit tendon tissues are calculated and analyzed. Quantitative analysis showed that tenocytes caused the decrease of tendon fibers retardance and the increase of standard deviation of tendon fibers orientation. The experimental results indicate that the retardance and the orientation angle parameters of the Mueller matrix can be used as quantitative indicators to distinguish rabbit tendon tissues with or without tenocytes and can reveal the structural characteristics of collagen fiber bundles, which may provide more useful information for the evaluation of tendon transplantation.

Mueller matrix polarimetry is regarded as a promising technique to comprehensively provide the optical and microstructural information of tissues. Especially, for pathological diagnosis, the Mueller matrix imaging can be used as a powerful tool to detect the structural features of abnormal tissue areas on pathological sections. However, a comparative study of the polarization characteristics of pathological sections with different preparation state is still needed to help decide which kinds of sections can be effectively used for polarization imaging diagnosis. In this paper, we apply the Mueller imaging polarimeter for quantitative detection of lung cancer section with the state of undewaxed, dewaxed and H-E stained at cellular-level respectively. The Mueller matrix polar decomposition parameters of the lung cancer section are calculated and analyzed. The results indicate that the polarization images of undewaxed section can reflect the morphology and arrangement of cells. The polarization images of dewaxed is more suitable for the quantitative analysis of tissue. The polarization images of stained sections are sensitive to the nucleus, which is suitable for the study of the internal structure of the nucleus.

One of the important and vital parameters in clinical applications is the human body’s core temperature. This study proposed a noncontact method using an infrared (IR) point detector to measure a thermal object’s internal temperature. An IR point detector constructed using a pinhole and a thermopile detects IR light only at the point located in imaging relation within a thermal object. This study introduced the 2D fast-scanning system to reduce a thermal filament image’s capturing time inside a miniature bulb. Although the thermopile’s response time could not follow the high-speed changes in IR intensity, the filament’s helical structure was disclosed in the condition of low background noise, resulting in decreased thermal images’ contrast and positional shifts of the measured filament.

Liver cancer is currently ranked to be the sixth most common cancer worldwide. Indeed, hepatocellular carcinoma (HCC) is the most frequent type of liver cancer. In this study, we applied an optical polarization system utilizing the Stokes-Mueller matrix to differentiate the HCC tissues with normal ones based on optical characteristics decomposed from the interaction of cancerous and normal tissues with polarized light. Nine optical parameters from tissues were extracted, specifically LB orientation angle (α), the LB phase retardance (β), the CB optical rotation angle (γ), the LD orientation angle (θd), the linear dichroism (D), the circular dichroism (R), the degrees of linear depolarization (e1 and e2), the degree of circular depolarization (e3), and the depolarization index (Δ). The experimental results showed that the orientation angle of linear birefringence (α), linear dichroism (D), and orientation angle of linear dichroism (θd) have the differences between cancerous and normal tissues. It promises a practical penetration to the optical characteristic of liver cancer based on Stokes-Mueller matrix polarimetry.

Fluorescence spectroscopy (FS) has been used to characterize tissue fluorophores in vivo for the diagnosis of precancers in the uterine cervix. In this study, a two-step curve fitting process is established to extract the intrinsic fluorescence intensity and spectrum of fluorophores including NADH and FAD in the epithelium and collagen crosslinks in the stroma. Forward Monte Carlo (MC) models of diffuse reflectance spectroscopy (DRS) and FS are replaced by artificial neuron networks to improve the computation speed. First, absorption and scattering coefficients of the two tissue layers and the epithelial thickness are estimated from DRS data. Second, the genetic algorithm is used to find the best set of intrinsic fluorescence parameters of the three fluorophores that best fit measured FS data. Results suggest that the two-layered tissue model outperforms conventional homogeneous tissue models in extracted tissue optical properties. Intrinsic fluorescence parameters are extracted from in-vivo spectra measured on 31 subjects.

Transcranial photobiomodulation (tPBM) has emerged as a novel non-invasive intervention for several neuropsychiatric or neurodegenerative conditions due to its neuroprotective and neuroenhancement effects by applying red/near-infrared (NIR) light to the forehead. tPBM has been applied to improve cognition in chronic traumatic brain injury, whereas tPBM-induced enhancement of the brain is dose-dependent and the effectiveness of each dose is affected by several factors such as the brain structure. In this study, we perform Monte Carlo simulations on 154 head models built with magnetic resonance images of healthy subjects, and propose a machine-learning based model that predicts the fraction of the energy of 1064-nm photons delivered to the gray matter (GM) based on the diffuse reflectance exiting the scalp surface (with wavelengths of 660, 730, 810, 850, and 940 nm) and demographic variables such as gender and age.

Early gingivitis is difficult to assess by visual observation. We found that the tissue chromophore values derived from our diffuse reflectance spectroscopy system had a greater advantage over the conventional 2-wavelength reflectance ratio method. In this research, the reflectance and absorption spectra were acquired from 28 healthy sites and 11 gingivitisinfected sites in 8 volunteer patients with illumination of the tungsten halogen lamps. Our results demonstrated that the method of chromophore values outperformed the 2-wavelength reflectance ratio method and gave a sensitivity of 64% and a specificity of 86%.

Due to the complex geometry of the oral cavity, it is challenging to perform wide-field optical coherence tomography (OCT) imaging of different regions of the oral mucosa, particularly in patients with opening difficulty due to submucosa fibrosis. In addition to changes in the tissue architectures, angiogenesis has been demonstrated to play an important role in the progression of oral neoplasm. In this study, we have developed a micromotor imaging catheter allowing high-speed and wide-field OCT and OCT angiography imaging of the oral mucosa. Leveraging polarization diversity detection, it ensures an optimal detection of the OCT signal for the entire circumference.

Recently, the functional extension of optical coherence tomography (OCT) with OCT angiography (OCTA) allows volumetric imaging of the subsurface microvasculature without requiring exogenous contrast agents like conventional angiography techniques. However, performing OCTA requires intensive computation to extract the changes of OCT signal due to moving red blood cells in the microvascular network. In this study, we have developed a graphic processing unit (GPU)-accelerated framework to realize high speed OCTA imaging and the visualization of the microvascular network after the data acquisition. In addition, we investigate the feasibility of providing real-time microvascular imaging leveraging dynamic scattering OCT and GPU.

We demonstrate widefield interferometric photothermal microscopy to detect the local refractive index changes of single nanoparticles induced by the dissipated heat due to light absorption (known as the thermal lens effect). The sensitivity of our system is sufficient for visualizing very small single gold nanoparticles, as small as 5 nm, with a dissipated heat of a few nanowatts. We establish a model to explain the generation mechanism of the photothermal signal. For small particles (< 40 nm), the photothermal signal is contributed by the scattered field of the thermal lens, independent of the particle size and materials. For large particles, we find that the strong scattered field of the sample would interfere with that of the thermal lens, leading to an enhancement of the photothermal contrast. This work shows that the complete scattering property of the sample is required for accurate absorption quantification through photothermal measurement.

Current optical microscope imaging heavily relies on fluorescence-based detection because of its high detection sensitivity and molecular specificity through labeling. However, the photophysics and photochemistry of the fluorophores, e.g., photobleaching, blinking and saturation, have limited its applicability to long-term observation and quantitative imaging. Label-free interference microscopy potentially overcomes the challenges aforementioned by measuring the scattered field of the sample quantitatively, but these approaches usually compromise on the sensitivity and molecular specificity of imaging. Here, we demonstrate coherent brightfield (COBRI) microscopy, a highly sensitive scatteringbased interference microscopy, to capture the dynamic linear scattering signal of live cell nucleus. We demonstrate a strategy to reconstruct the nuclear organization from the time-lapse COBRI imaging. Our method offers the opportunity to investigate the cell nuclear dynamics at the unprecedented spatial and temporal resolutions.

Understanding the propagating of light in biological tissues have long been an important issue. For this purpose, modeling scattering of light from laser radiation into turbid media has been studied. One of the common modeling tools is Monte Carlo simulation, and Mueller matrix method is a commonly used technique to study birefringence and depolarization properties of biological samples. Based on electric field Monte Carlo simulation in this paper, we present backscattering Muller matrix calculations for different size of particles and performed comparative studies. Our results may find important applications in laser tissue interaction.

In this paper a pH monitoring system is demonstrated by utilizing wavelength modulated fiber optic techniques. A stimulus responsive hydrogel which exhibits a volume change with the change of pH is utilized to render a strain on Fiber Bragg grating (FBG). The gel is synthesized from the blends of Poly (vinyl alcohol)/Poly (acrylic acid). The induced strain causes a FBG peak shift that can be used as a measure of pH change. The proposed sensing system exhibits a good linearity in acidic pH range of 3 to 7 with a sensitivity of 250 pm/pH. Besides that it is very cost effective, bio degradable and also possess repeatability.

The present article proposes carcinogenic Chromium (VI) metal ion sensor by a hydrogel coated etched Fiber Bragg grating (FBG). Hydrogel synthesized from the blends of 3-arylamidopropyltrimethylammoniumchloride (ATAC) which is stimulus responsive to chromium ions suffers a volume change in different Cr solutions. Upon exposure to various concentrations of Cr (VI) ion solutions, FBG peak is shifted due to the mechanical strain induced by the stimulus swelling property of the hydrogel. The peak shift is correlated with the concentration of the Cr (VI) metal ion. Thus a Chemo-mechanical- optical sensing approach for the detection of Cr (VI) is studied. Trace amounts of Chromium (VI) ion as low as 10 ppb can be estimated by the method. The resolution of the sensor system is found to be 0.05 ppb.

Serving as minimally invasive surgery, robotic surgery has become a promising treatment approach toward various diseases, such as Urology, Gastroenterology, or Gynecology. Although robotic surgery exhibits several advantages of decreasing the incision size and shorter patient stay, it still imposes extensive labor loading to the surgeons. Therefore, recently, semiautonomous laparoscope surgery has been emerged to improve the surgery precision further. In this study, we have developed a miniature imaging head combing wide-angle camera and optical coherence tomography aiming for semiautonomous laparoscope surgery. Leveraging the ranging information provided from OCT, it allows more agile control of the imaging head.

Quantification of cardiac dynamics of Zebrafish larvae using lightsheet fluorescence microscopy

The purpose is to utilize infrared-ray thermal imaging system to detect thermal temperature of the target, and the appearance of image by the digital image processing. The image of the infrared-ray thermal imager could get the related position and size of the lymphedema. The experiment measured the noncontact measurement of infrared images in the knee, calf belly and ankle of the patient's lower limb edema to observe the magnitude of its edema. The image was processed by Canny edge detection and marking method. The growing rate of knee, calf, and ankle were 4.35, 18.18, 13.64%, respectively. The position of calf had the largest growing rate than that of other positions.

Facial masks are known to moisturize skin to maintain proper skin health. The global sheet face mask market size was valued at USD 257.9 million in 2018. Nevertheless, there are few academic literatures to discuss the effect of facial mask on skin. In this study, we compare the commercially available instrument with our DRS system by measuring the skin after applying facial masks. The results show that our DRS system can effectively quantify the variations of skin hydration and redness induced by the application of facial masks.

For acquiring optically sectioned images of volumetric samples from multiple depths without axial scanning, a confocal system which is able to obtain multi-plane images with a Digital Micro-Mirror Device (DMD) has been proposed. The focal points of the laser beam can be arbitrarily positioned to any multiple planes in the three dimensional object space by switching multiplexed binary hologram encoded in the DMD by Lee hologram. The radius of the spherical wavefronts generated directly determines the location of the focal points and DMD can function either as a convex or concave mirror. The optical sectioning capabilities of system are verified and which can be applicable in various biomedical imaging applications.

A volume holographic optical element is designed and fabricated using photopolymer (PQ-PMMA) for super Gaussian beam. A Lee hologram and Digital Micro Mirror Device (DMD) are used for modulating the laser beam to a uniform one all over its beam diameter. The efficiency and uniformity of super Gaussian beams generated through volume holographic optical component is experimentally demonstrated with optimized parameters. Super Gaussian beam generated by volume holographic grating with unique diffractive properties are advantageous for variety of laser applications.

Differential phase contrast microscopy based on twelve-axis measurements of half-circle pupil acquires isotropic phase information but suffers with poor imaging speed. We proposed a new method by modulating illumination pattern to realize isotropic PTF within three-axis measurements. Not only provide phase information reconstruction under isotropic phase transfer function in fast imaging speed but also avoid particular imaging issue including motion-blur and lowillumination images. By modulate illumination pattern with programmable thin-fin-transistor(TFT) panel as digital pupil, we design radially asymmetric pupil to achieve isotropic PTF within three-axis measurements. To further improve imaging speed, wavelength-multiplexing approach is implemented by color camera. By pupil engineering, 12-times imaging speed improvement compared with twelve-axis measurements of half-circle pupil is attained. Color-leakage, which is the cross-talk under wavelength-multiplexing, was already calibrated by color-leakage correction as well. Meanwhile, accuracy of phase recover reach 97% by using 10μm polystyrene microspheres to guarantee correct result. In our method, color radially asymmetric pupil based on pupil engineering provide lots superiority including high imaging speed, measurement under isotropic phase transfer function, high accuracy of phase recover and immune from imaging issue such as motion-blur and low-illumination images.

We present a telecentric design to obtain constant magnification with long axial scanning range in an optical sectioning microscope. A Moiré lens is included and utilized for this purpose. The design principles of our system are explained through mathematical expression and simulation results are provided for different conditions, which include the case of variation displacement of the focal plane with different Moiré lens focal length, and the scanning range in terms of the magnification value. Furthermore, we also use the Zemax ray-tracing simulation method to show the telecentric examples for different magnification value with corresponding Moiré lens focal length.

Metasurfaces comprising 3D chiral structures have shown great potential in chiroptical applications such as chiral optical components and sensing. So far, the main challenges lie in the nanofabrication and the limited operational bandwidth. Here, we present an effective nanofabrication method to create a 3D chiral metasurface with far- and nearfield broadband chiroptical properties. A focused ion beam is used to cut and stretch nanowires into 3D Archimedean spirals from stacked films. The spiral exhibits far- and near-field broadband chiroptical responses from 2 to 8 μm. With circularly polarized light (CPL), the spiral shows superior far-field transmission dissymmetry and handedness-dependent near-field localization. The reported method and chiral metasurface may find applications in broadband chiral optics and chiral sensing.

The laser treatment is an ideal option to conduct a surgical resection since it enables to provide higher accuracy and to cause less damage when targeting invariant tissue areas. Compared to traditional mechanical or chemical treatment modalities, it can shrink or destroy cancer cells using a narrow, focused light beam without harming normal tissue nearby. Laser speckle contrast image (LSCI) is a powerful technology that is able to capture dynamic changes of backscattered light, and then, convert it to relative flow using speckle contrast analysis. When the coherent light illuminates biological tissue, random interference patterns will be received at the detector. If the particles are moving, patterns will result in fluctuation as known as speckle patterns. By setting the exposure time equal to or longer than the speckle fluctuation duration, such intensity fluctuation can be recorded, forming the speckle image. Since red blood cell is the primary moving particles in vessels, the blurring can be related to flow information. Previous reports have also indicated that the autocorrelation time is inversely related to the blood flow velocity. As a result, microvasculature and blood flow data can be represented by analyzing the speckle variance of biological tissue spatially and temporarily. In this study, we propose to use LSCI to in vivo investigate the induced thermal effect by laser illumination, and the difference in the thermal effect caused by the CW and pulsed lasers will be compared. Finally, the treatment outcomes on brain tumor will be also compared.

Optical coherence tomography (OCT) can noninvasively reconstruct the three-dimensional microstructure of skin and OCT has been commonly used for clinical studies. Additionally, the functional imaging abilities have been intensively investigated in the past few years such as angiography, spectroscopy, polarization, elasticity, etc. The previous reports have demonstrated that OCT can be a powerful tool for diagnoses of skin disorders. Vitiligo is a skin disorder by losing the pigment and the skin patches become white and have sharp margins. Generally, the patches start on the skin areas which are exposed to the sun. However, it is difficult to be identified before skin becomes white. Therefore, an imaging tool is required for diagnosis of the early-stage skin vitiligo. In this study, we use OCT for in vivo imaging of skin vitiligo and OCT is able to identify the loss of pigment in the early stage. The results demonstrated OCT could be a potential tool for the diagnosis of the early-stage vitiligo.

The feature of rapid divergence of conventional Gaussian beam restricts the field of view in light sheet microscopy. Comparison with Gaussian beam, the Airy beams provides many advantages in light sheet microscopy such as larger field of view (FOV), longer penetration path, and self-reconstruction. C. elegans is a model organism for developmental biological studies. Here, we design Airy light sheet microscope to perform in-vivo imaging of C. elegans. A spatial light modulator is used to generate 1D Airy beam for illumination purpose. Imaging performance is experimentally evaluated for our system. Present results may find important applications for studying internal structures in-vivo imaging of C. elegans.

Isotropic quantitative differential phase contrast (iDPC) microscopy based on pupil engineering has made significant improvement in reconstructing phase image of weak phase objects. In previous researches, the pupil designs have been investigated for enhancing the data acquisition efficiency. To further improve the phase retrieval procedure in iDPC, we adapt deep neural networks to achieve isotropic phase distribution from half-pupil based quantitative differential phase contrast (qDPC) microscopy. In this study, we utilized U-net model for mapping from 1-axis phase reconstruction to 12- axis one. The results show that the deep neural network we proposed achieved expecting performance. The final testing loss value of our model after 1000 epochs of training achieved 6.7e-5 after normalized. The peak signal to noise ratio improvement is from 26dB to 30dB.