Session Index

Cell imaging largely relies on fluorescence-based microscopy because of the high detection sensitivity and molecular specificity achieved by labeling the sample with fluorophores. Unfortunately, resolving nanoscopic cell dynamics remains a challenge due to the photobleaching of fluorophores. In this talk, I will present scattering-based optical interference microscopy that facilitates direct visualization of nano-dynamics in living cells. The linear scattering signal is stable and indefinite, supporting sensitive and precise measurements at a high speed. Using common-path interferometry, the scattering imaging is highly sensitive, enabling direct observation of nano-sized biological objects. With proper image data analysis, organelle specific, high-resolution cell images can be obtained without any labels. Using our methods, rapid biological processes occurring in the millisecond timescale are resolved at high spatiotemporal resolution, including remodeling of chromatin and endoplasmic reticulum network. The label-free optical interference microscopy offers the opportunity to explore nanoscale cell dynamics with unprecedented details

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We demonstrated three-photon fluorescence microscopy for drosophila brain imaging based on a 24-MHz Cr:forsterite oscillator. We studied the soliton mode-locking dynamics to optimize the output pulse width and peak power by managing the intracavity dispersion. We have realized three-photon fluorescence imaging, and the imaging contrast and penetration depth are much better than the results obtained from the two-photon excitation. Moreover, we found that the signal-to-background ratio at depth is greatly improved when using shorter pulses from the laser oscillator. For functional imaging applications, we also demonstrated three-photon calcium imaging stimulated by an external electric shock.

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Early diagnosis of esophageal cancer is effective in treatment. Currently, computer aid in endoscopic image classification tasks has achieved remarkable achievements. A total of 936 endoscopic images were used for the training, which included 498 white-light images (WLI) and 438 narrow-band images (NBI). The esophageal neoplasms are classified into 3 groups: squamous cell carcinoma, dysplasia, and normal. Vision Transformer is proposed to improve prediction results. The prediction results are as follows: 93.55% of accuracy, and f1-score 92.86%, respectively.

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Glycated-hemoglobin- (HbA1c-) fraction is universally used in diagnosing diabetes and guiding therapy. Our recent efforts indicate that by analyzing the HbA1c distribution of red blood cells (RBCs), one could further unravel the much-needed information of glycemic variability. Here, we introduce spectrally-resolved third-harmonic-generation (srTHG) microscopy, which for the first time noninvasively provide the HbA1c imaging at the single-RBC level and map the HbA1c distributions clinically.

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In this study, we aim to figure out a better instruction method. We apply two instruction method, traditional didactic instruction (TDI) and interactive response system multiple assessment-assisted instructions (IRSAI) to senior high school education. To evaluate the effect on students’ cognitive function, we record the changes in cerebral oxygen concentration in the prefrontal cortex via functional near-infrared spectroscopy (fNIRS). Then, feed the proceed data into a machine learning model to classify, and get the training accuracy and testing accuracy of 85% and 80%, proving the feasibility of instruction evaluation via fNIRS.

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A swept-source optical coherence tomography (SS-OCT) is a non-invasive imaging technique with high resolution in a small area. A fiber-based auxiliary interferometer is implemented in SS-OCT to the correct spatial distance error from laser output nonlinearity. To
deliver the chip-based SS-OCT, a delayed Mach-Zehnder interferometer built with two broadband couplers on the silicon-on-insulator platform demonstrates the axial resolution of 20 mm through the zero-crossing resampling.

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A grating coupler-based spectral-domain optical coherence tomography is miniaturized through the photonic integrated circuit technology on a silicon-on-insulator platform. We present the design and technology verification of a Mach-Zehnder typed broadband coupler. The experimental results showed that the A-scan depth information after signal processing was 22.92 um and 48.5 dB for longitudinal resolution and sensitivity, respectively.


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