Browsing by Author "Chan, Ming-Che"

Now showing 1 - 20 of 26

Chromatic confocal microscopy to rapidly reveal nanoscale surface/interface topography by position-sensitive detection
(2018-08-20)
Zhuo, Guan-Yu
;
Hsu, Chia-Huan
;
Wang, Yen-Hsiang
;
Chan, Ming-Che
;
光電系統研究所
This paper presents a confocal microscope for the rapid and noninvasive capture of threedimensional (3D) images showing the surface/interface topography in a far-field configuration. The proposed microscope features a nanoscale optical ruler capable of performing fast depth measurements based on the chromatic aberration of microscope objectives. A diffraction grating and a position-sensitive detector were used to extract the spectral shift, which directly maps the height of the surface with a nanoscale resolution. Because neither the mechanical scanning nor the spectrometer, which limit the speed of 3D imaging, are needed in the axial direction, full 3D surface topography images with nanoscale depth resolution can be acquired rapidly using the nanoscale optical ruler in conjunction with 2D lateral beam scanning. The presented technique overcomes the limitation of the detection speed of conventional chromatic confocal microscopy. In experiments, the 3D static and dynamic nanoscale surface profiles of several representative optoelectronic and electronic devices were demonstrated. This fast and non-invasive approach with nanoscale depth resolution to the measurement of topography images has considerable promise in academic research and industrial applications. Published by AIP Publishing.
Direct observation of dynamic thermal lensing in nanoscale surfaces/interfaces of end-pumped Nd:YVO4 laser
(2020-05-26)
Lin, Shou-Tai
;
Hung, Wei-Kuo
;
Zhuo, Guan-Yu
;
Wang, Hsien-Yi
;
Chan, Ming-Che
This work describes non-invasive observations of dynamic thermal lensing in an end-pumped Nd:YVO4 laser. Measurements were obtained with a nanoscale optical ruler created using chromatic aberrations, pinholes, dispersive gratings, and position-sensitive detectors. This study reports on variations in thermally induced oscillations and on underdamping behavior in the regime of high pump power. Dynamic data related to the thermal behavior can be used to study the balance between driving forces (pumping and thermal stresses) and damping losses (cooling and output coupling). The non-invasive nature of the proposed scheme along with its sub-100-nm axial resolution, sub-millisecond time resolution, and simple configuration makes it widely applicable for studying heat-related phenomena within laser crystals. The preliminary results show that such non-invasive methods could be used to detect thermally induced nanoscale deformations in integrated circuits, high-power optoelectronic devices, and optical devices with high-power illumination.
Electro-optical measurement and process inspection for integrated gate driver circuit on thin-film-transistor array panels
(2015-06-01)
Wang, Yao-Chin
;
Lin, Bor-Shyh
;
Chan, Ming-Che
;
光電系統研究所
;
影像與生醫光電研究所
The study proposed electro-optical measurement and process inspection for integrated-gate-driver circuit on thin-film-transistor array panel. It is a trend on the developing with application of integrated gate driver circuit in the narrow frame design and reduction of driver integrated circuit chips in thin-film-transistor array backplane. Over the past, it cannot detect that contain integrated-gate-driver circuit on thin-film-transistor array panel, especially in process defects of the integrated-gate-driver circuit. The paper proposed a process inspection for the defects in integrated-gate-driver circuit on the thin-film-transistor array panel by the voltage imaging technique and reported good performance. (C) 2015 Elsevier Ltd. All rights reserved.
Estimation on the effect of local brain cooling after head injury by wireless near infrared spectroscopy
(2017-02)
Wang, Che-Chuan
;
Wang, Yao-Chin
;
Liao, Yi-Chien
;
Wang, Jhi-Joung
;
Chan, Ming-Che
Local brain cooling is a way to treat traumatic brain injury and prevent secondary brain injury. The aim of this study is to explore the change of hemoglobin during local brain cooling after traumatic brain injury, and assess the treatment effect by using the wireless near infrared spectroscopy (NIRS) system. Assign all male Sprague Dawley rats to three groups randomly: sham, fluid percussion injury (FPI), FPI + cooling. After executing fluid percussion injury, a cold water bag (5-6 degrees C) was used locally for 30 min. The wireless NIRS system which we developed was used to monitor the concentration change of HbO(2), HbR and HbT. And other physiological parameters, ICP and CPP, were also monitored during the experiment. According to previous results, local brain cooling could reduce infarction volume while traumatic brain injury occurs. Similarly, our results show that local brain cooling caused oxy-hemoglobin, the tissue oxygen saturation and CPP increase and ICP decreased. From the results, the hemoglobin parameters, ICP and MAP were affected by temperature. And local cooling after FPI might have clinical benefits in the future. In addition, the wireless NIRS system might be an instrument to assess the effect of hypothermia. (C) 2016 Elsevier Ltd. All rights reserved.
High power NIR fiber-optic femtosecond Cherenkov radiation and its application on nonlinear light microscopy
(2014-04-21)
Chan, Ming-Che
;
Lien, Chi-Hsiang
;
Lu, Jyan-Yo
;
Lyu, Bo-Han
;
影像與生醫光電研究所
We reported a record high power (>250 mW) and compact near-infrared fiber-optic femtosecond Cherenkov radiation source and its new application on nonlinear light microscopy for the first time (to our best knowledge). The high power femtosecond Cherenkov radiation was generated by 1.03 mu m femtosecond pulses from a portable diode-pumped laser and a photonic crystal fiber as a compact, flexible, and highly efficient wavelength convertor. Sectioned nonlinear light microscopy images from mouse brain blood vessel network and rat tail tendon were then performed by the demonstrated light source. Due to the advantages of its high average output power (>250 mW), high pulse energy (>4 nJ), excellent wavelength conversion efficiency (>40%), compactness, simplicity in configuration, and turn-key operation, the demonstrated femtosecond Cherenkov radiation source could thus be widely applicable as an alternative excitation source to mode-locked Ti:Sapphire lasers for future clinical nonlinear microscopy or other applications requiring synchronized multi-wavelength light sources. (C) 2014 Optical Society of America
Higher-order modulations of fs laser pulses for GHz frequency domain photon migration system
(2014-02-24)
Lin, Huang-Yi
;
Cheng, Nanyu
;
Tseng, Sheng-Hao
;
Chan, Ming-Che
;
影像與生醫光電研究所
Except the fundamental modulation frequency, by higher-order-harmonic modulations of mode-locked laser pulses and a simple frequency demodulation circuit, a novel approach to GHz frequency-domain-photon-migration (FDPM) system was reported. With this novel approach, a wide-band modulation frequency comb is available without any external modulation devices and the only electronics to extract the optical attenuation and phase properties at a selected modulation frequency in FDPM systems are good mixers and lock-in devices. This approach greatly expands the frequency range that could be achieved by conventional FDPM systems and suggests that our system could extract much more information from biological tissues than the conventional FDPM systems. Moreover, this demonstration will be beneficial for discerning the minute change of tissue properties. (C) 2014 Optical Society of America
Hotspot Detection in Integrated Circuits by Two-photon-fluorescence-based Thermal Microscope
(2018-01-01)
Zhuo, Guan-Yu
;
Yang, Zu-Po
;
Chan, Ming-Che
;
光電系統研究所
;
Institute of Photonic System
For thermal images and related hotspot diagnosis on integrated circuits (ICs) during operation, we present a high temporal, spatial, and temperature resolution thermal microscope based on the thermal-optical properties of R6G thin film.
In situ high-resolution thermal microscopy on integrated circuits
(2017-09-04)
Zhuo, Guan-Yu
;
Su, Hai-Ching
;
Wang, Hsien-Yi
;
Chan, Ming-Che
;
光電系統研究所
The miniaturization of metal tracks in integrated circuits (ICs) can cause abnormal heat dissipation, resulting in electrostatic discharge, overvoltage breakdown, and other unwanted issues. Unfortunately, locating areas of abnormal heat dissipation is limited either by the spatial resolution or imaging acquisition speed of current thermal analytical techniques. A rapid, non-contact approach to the thermal imaging of ICs with sub-mu m resolution could help to alleviate this issue. In this work, based on the intensity of the temperature-dependent two-photon fluorescence (TPF) of Rhodamine 6G (R6G) material, we developed a novel fast and non-invasive thermal microscopy with a sub-mu m resolution. Its application to the location of hotspots that may evolve into thermally induced defects in ICs was also demonstrated. To the best of our knowledge, this is the first study to present highresolution 2D thermal microscopic images of ICs, showing the generation, propagation, and distribution of heat during its operation. According to the demonstrated results, this scheme has considerable potential for future in situ hotspot analysis during the optimization stage of IC development. (C) 2017 Optical Society \of America
Label-free characterization of collagen fibers in cancerous esophagus tissues using ratiometric nonlinear optical microscopy
(1970-01-01)
Chen, Wei-Chung
;
Chen, Yu-Jen
;
Lin, Shih-Ting
;
Hung, Wei-Han
;
Chan, Ming-Che
A quantitative analytical method to discriminate among the various types of cancerous esophagus tissue is essential for accurate cancer staging. This paper reports on the use of ratiometric nonlinear optical microscopy to reveal the ratio of two-photon excited fluorescence (TPEF) to second harmonic generation (SHG) and forward to backward (F/B) SHG from single collagen fibers only in submucosa of esophageal squamous cell carcinoma. This makes it possible to accurately differentiate among the four stages of esophageal cancer, providing results that are in good agreement with histopathology. Furthermore, it is confirmed by polarization-dependent SHG that the varied SHG response in esophageal cancer tissues is mainly from the shrinkage in diameter of collagen fibers instead of the collagen triple helixes altered by cancer cells. Based on the results of TPEF/SHG and F/B SHG ratio, they can cooperatively improve the precision of diagnostics on esophageal cancer and could be transferred to other types of cancer diseases with changed collagen fibers. Impact statement The issue of classifying esophageal cancer at various developmental stages is crucial for determining the optimized treatment protocol for the patients, as well as the prognosis. Precision improvement in staging esophageal cancer keeps seeking quantitative and analytical imaging methods that could augment histopathological techniques. In this work, we used nonlinear optical microscopy for ratiometric analysis on the intrinsic signal of two-photon excited fluorescence (TPEF) and second harmonic generation (SHG) from single collagen fibers only in submucosa of esophageal squamous cell carcinoma (ESCC). The blind tests of TPEF/SHG and forward (F)/backward (B) SHG were demonstrated to compare with the histology conclusion. The discussion of sensitivity and specificity was provided via statistical comparison between the four stages of esophageal cancer. To the best of our knowledge, this is the first study of using these two ratios in combination for staging ESCC.
Mechanical Scan-Free Confocal Microscope by a Broadband Source and Two Balanced Wavelength-to-Space Transformations
(2015-02-01)
Wang, Hsien-Yi
;
Lin, Bor-Shyh
;
Lou, Chien-Ya
;
Chan, Ming-Che
;
光電學院
A new approach for performing confocal microscopy without no mechanical scanners was reported by a broadband light source, two similar 2-D wavelength-dispersive optical elements, and an uncooled charge-coupled device (CCD). In the new approach, 2-D sample structures were simultaneously and instantly mapped into the CCD by performing two balanced wavelength-to-space transformations and one spaceto- wavelength transformation. Compared with a traditional mechanical-scanner-based confocal microscope, no mechanical scanners or additional post dataprocessing were required in this new approach. The sectioned images are directly shown in the CCD. The demonstrated balanced wavelength-encoded confocal microscope has a simple configuration and shows great potential for high imaging speed. It has the advantage of miniaturized packaging and other applications outside of the laboratory as well.
Non-invasive biopsy of doped-ions inside optical substrate by modified two-photon microscopy
(2015-01-26)
Wang, Yao-Chin
;
Chen, Hsiang-Ning
;
Li, Wang-Yang
;
Chan, Ming-Che
;
光電系統研究所
Doped-ion based optical elements play key roles in optical signal processes, including amplification, absorption, wavelength-filtering, lighting, and polarizing plate. Non-invasively mapping the spatial distribution of the ion concentrations in these optical elements is highly desirable either during the fabrication process or to determine their optical qualities. In this work, we applied modified two-photon fluorescence (mTPF) microscopy to trace the ion-distributions deep inside the optical elements. For demonstration purposes, polyvinyl alcohol (PVA) polymer films inside polarizing plates are taken as an example, where the spatial distributions of Iodine-dyed ions were measured by the m-TPF microscope in a fast and non-invasive way. The durability of the polarizer films can be distinguished from the axial distribution of the Iodine-dyed ions, without the need to perform a biopsy. This proposed method and demonstrated results show great potential for monitoring the spatial distributions of doped-ions in the optical elements quickly and non-destructively, which would be of great benefit in both scientific research and industrial applications. (C) 2015 Optical Society of America
Non-invasive image-guided laser microsurgery by a dual-wavelength fiber laser and an integrated fiber-optic multi-modal system
(2016-10-15)
Tsai, Meng-Tsan
;
Li, Dean-Ru
;
Chan, Ming-Che
;
光電系統研究所
;
Institute of Photonic System
A new approach to non-invasive image-guided laser micro-treatment is demonstrated by a dual-wavelength fiber laser source and an integrated fiber-based multi-modal system. The fiber-based source, operated in 1.55 and 1.2 mu m simultaneously, was directly connected to an integrated fiber-based multi-modal system for imaging and laser micro-treatment at the same time. The 1.2 mu m radiations, within the 1.2-1.35 mu m bio-penetration window of skin, were utilized for spectral domain optical coherence tomography imaging. The 1.55 mu m radiations, highly absorptive to waters, were utilized for laser microsurgery. The new approach, which is simple in configuration and accurately controls the positions and exposure time of the laser microsurgery, shows great promises for future clinical applications. (C) 2016 Optical Society of America
Nonlinear Light Microscopy by a 1.2-mu m Fiber-Laser-Based Femtosecond Dispersive Wave Source
(2015-06-01)
Wang, Hsien-Yi
;
Huang, Shiuan-Wen
;
Li, Dean-Ru
;
Lin, Bor-Shyh
;
Chan, Ming-Che
A fiber-laser-based femtosecond dispersive wave laser source, operated within the 1.2-to 1.3-mu m bio-penetration wavelength window, and its application on nonlinear light microscopy were both demonstrated in this paper. This portable 1.2-mu m femtosecond fiber-optic source was composed of an all-fiber 1.55-mu m mode-locked erbium-doped fiber laser as the excitation source and a nonlinear fiber as a frequency up converter. The 1.2-mu m femtosecond radiations with an up to a 55-mW output power and a 125-fs pulsewidth were experimentally demonstrated. By the fiber-based 1.2-mu m femtosecond dispersive wave source, nonlinear laser scanning microscopy, including two-photon fluorescence and second-harmonic generation microscopy, was also performed within the 1.2-to 1.3-mu m bio-penetration window in this report. The fiber-based 1.2-mu m femtosecond light source, with a simple system configuration, turn-key operation, and a miniaturized package, shows great potential for nonlinear light microscopy and other related applications outside of the laboratory.
Novel Wearable and Wireless Ring-Type Pulse Oximeter with Multi-Detectors
(2014-09-01)
Huang, Cheng-Yang
;
Chan, Ming-Che
;
Chen, Chien-Yue
;
Lin, Bor-Shyh
;
影像與生醫光電研究所
The pulse oximeter is a popular instrument to monitor the arterial oxygen saturation (SPO2). Although a fingertip-type pulse oximeter is the mainstream one on the market at present, it is still inconvenient for long-term monitoring, in particular, with respect to motion. Therefore, the development of a wearable pulse oximeter, such as a finger base-type pulse oximeter, can effectively solve the above issue. However, the tissue structure of the finger base is complex, and there is lack of detailed information on the effect of the light source and detector placement on measuring SPO2. In this study, the practicability of a ring-type pulse oximeter with a multi-detector was investigated by optical human tissue simulation. The optimal design of a ring-type pulse oximeter that can provide the best efficiency of measuring SPO2 was discussed. The efficiency of ring-type pulse oximeters with a single detector and a multi-detector was also discussed. Finally, a wearable and wireless ring-type pulse oximeter was also implemented to validate the simulation results and was compared with the commercial fingertip-type pulse oximeter.
Observation of spontaneous polarization misalignments in periodically poled crystals using second-harmonic generation microscopy
(2011-06-06)
Tzeng, Yu-Yi
;
Zhuo, Zong-Yan
;
Lee, Ming-Yin
;
Liao, Chien-Sheng
;
Wu, Pei-Chun
Periodically poled crystal (PPC) is a key component for nonlinear optical applications. Its poling quality relies largely on successful domain inversion and the alignment of spontaneous polarization (SP) vectors in each domain. Here we report the unexpected observation of bulk second harmonic generation (SHG) in PPC when excitation propagating along its optical axis. Based on its tensorial nature, SHG is highly sensitive to the orientation of SP, and therefore the misalignment of SP in each domain of PPC can be revealed noninvasively by SHG microscopy. This nonlinear imaging modality provides optical sectioning capability with 3D sub-micrometer resolution, so it will be useful for in situ investigation of poling quality in PPC. (C) 2011 Optical Society of America
Optical coherence tomography-guided laser microsurgery for blood coagulation with continuous-wave laser diode
(2015-11-16)
Chang, Feng-Yu
;
Tsai, Meng-Tsan
;
Wang, Zu-Yi
;
Chi, Chun-Kai
;
Lee, Cheng-Kuang
Blood coagulation is the clotting and subsequent dissolution of the clot following repair to the damaged tissue. However, inducing blood coagulation is difficult for some patients with homeostasis dysfunction or during surgery. In this study, we proposed a method to develop an integrated system that combines optical coherence tomography (OCT) and laser microsurgery for blood coagulation. Also, an algorithm for positioning of the treatment location from OCT images was developed. With OCT scanning, 2D/3D OCT images and angiography of tissue can be obtained simultaneously, enabling to noninvasively reconstruct the morphological and microvascular structures for real-time monitoring of changes in biological tissues during laser microsurgery. Instead of high-cost pulsed lasers, continuous-wave laser diodes (CW-LDs) with the central wavelengths of 450 nm and 532 nm are used for blood coagulation, corresponding to higher absorption coefficients of oxyhemoglobin and deoxyhemoglobin. Experimental results showed that the location of laser exposure can be accurately controlled with the proposed approach of imaging-based feedback positioning. Moreover, blood coagulation can be efficiently induced by CW-LDs and the coagulation process can be monitored in real-time with OCT. This technology enables to potentially provide accurate positioning for laser microsurgery and control the laser exposure to avoid extra damage by real-time OCT imaging.
Signal Enhancement by Fiber-Dispersion in Sub-GHz Frequency Domain Biophotonic Diagnosis Systems
(2019-01-01)
Tseng, Sheng-Hao
;
Huang, Tzu-Feng
;
Yeh, Jun-Liang
;
Chan, Ming-Che
;
光電學院
Pulsed lasers can be utilized to generate intensitymodulated light at the fundamental frequency of the laser repetition rate as well as higher order modulation (HOM) frequencies in the recent study. We also demonstrated the feasibility of using pulse lasers and fiber-wavelength-convertors as a light source in multicolor frequency-domain (FD) biophotonic systems. In this paper, we present a novel approach to enhancing the intensity of signals below 1 GHz in HOM-based FD systems simply by employing the fiber dispersion effect. The energy spectrum of HOMs can be redistributed to enhance the intensity of HOMs within the bandwidth of the photo-detector without the need for an external (optical or electrical) amplifier. We also demonstrate that the length of dispersive fiber can be optimized via numerical calculations, the results of which are in good agreement with experimental measurements. Finally, we demonstrate a frequencydomain-photon-migration system employing the fiber dispersion effect to enhance sub-GHz signals at a wavelength of 1.03 pro in order to recover the optical properties of turbid samples. Our measurements results demonstrate the superiority of the proposed FD source over the conventional directly modulated FD light source. Furthermore, the simple configuration of the proposed scheme makes it applicable to a wide range of FD biophotonic systems.
Simple approach to three-color two-photon microscopy by a fiber-optic wavelength convertor
(2016-11-01)
Li, Kuen-Che
;
Huang, Lynn L. H.
;
Liang, Jhih-Hao
;
Chan, Ming-Che
;
光電學院
A simple approach to multi-color two-photon microscopy of the red, green, and blue fluorescent indicators was reported based on an ultra-compact 1.03-mu m femtosecond laser and a nonlinear fiber. Inside the nonlinear fiber, the 1.03-mu m laser pulses were simultaneously blue-shifted to 0.6 similar to 0.8 mu m and red-shifted to 1.2 similar to 1.4 mu m region by the Cherenkov radiation and fiber Raman gain effects. The wavelength-shifted 0.6 similar to 0.8 mu m and 1.2 similar to 1.4 mu m radiations were co-propagated with the residual non-converted 1.03-mu m pulses inside the same nonlinear fiber to form a fiber-output three-color femtosecond source. The application of the multi-wavelength sources on multi-color two-photon fluorescence microscopy were also demonstrated. Overall, due to simple system configuration, convenient wavelength conversion, easy wavelength tunability within the entire 0.7 similar to 1.35 mu m biopenetration window and less requirement for high power and bulky light sources, the simple approach to multi-color two-photon microscopy could be widely applicable as an easily implemented and excellent research tool for future biomedical and possibly even clinical applications. (C) 2016 Optical Society of America
Simultaneous 0.8, 1.0, and 1.3 mu m multispectral and common-path broadband source for optical coherence tomography
(2014-02-15)
Tsai, Meng-Tsan
;
Chan, Ming-Che
;
影像與生醫光電研究所
;
Institute of Imaging and Biomedical Photonics
Simultaneous multispectral generation in 0.8, 1.0, and 1.3 mu m wavelength ranges by efficient energy conversions of 1.0 mu m wavelength femtosecond pulses through a nonlinear fiber was reported. The output spectral range of this multispectral light source was composed of 0.6-0.9 mu m blue-shifted Cherenkov radiation (CR), 1.0 mu m residual pump, and 1.1-1.7 mu m red-shifted soliton self-frequency shift (SSFS) with more than 1 mW/nm power-spectral densities. Output characteristics of the multispectral light source were then quantitatively analyzed and the central wavelengths of CR and SSFS emissions can be further easily adjusted by changing the input power into wavelength conversion fiber. Example spectral-domain optical coherence tomography (OCT) images of an IR card and finger skin were also performed with the demonstrated source. Due to the advantages of its simplicity, easily operated, and wavelength tunability, the reported multispectral source could be widely applicable for various spectroscopic OCT applications. (C) 2014 Optical Society of America
Spiral surface plasmon modes inside metallic nanoholes
(2015-11-16)
Chen, Chih-Min
;
Ke, Jian-Liang
;
Lan, Yung-Chiang
;
Chan, Ming-Che
;
光電學院
Spiral surface plasmon (SSP) modes that propagate inside a silver (Ag) nanohole are investigated by performing both simulations and theoretical analyses. The SSP modes are formed by a linear combination of two rotating SP eigenmodes of the Ag nanohole in the fast-wave branch. Inside a uniform Ag nanohole, the handedness and the number of strands of the SSP modes are determined by both the component SP eigenmodes and their rotation directions. The spiral pitch of the SSP mode increases with the nanohole radius for a fixed wavelength and is inversely related to the incident wavelength for a fixed nanohole radius. Inside a tapered Ag nanohole, the spiral pitch decreases with the reduction of nanohole radius. However, the azimuth-integrated field energy density increases to a maximum value and then falls. For a tapered Ag-clad fiber capped by a tapered Ag nanorod, the SSP mode reverses its handedness when it passes through the fiber-nanorod interface. Furthermore, using this composite structure, the field energy density of SSP mode that arrives at the tip of the tapered nanorod is largely increased. (C) 2015 Optical Society of America