Prof. Fu-Jen Kao Profile

Prof. Fu-Jen Kao

Distinguished Professor at National Yang Ming Chiao Tung Univ

SPIE Involvement:

Conference Program Committee | Author

Publications (46)

Proceedings Article | 15 March 2023 Presentation

Toward high throughput 3D connectome imaging (Conference Presentation)

Fu-Jen Kao, Ann-Shyn Chiang, Scotte Liu, Tiffany Kao, Daniel Wu, Wei-Kun Chang, Henry Liu, Jerry Wong

Proceedings Volume PC12384, PC123840M (2023) https://doi.org/10.1117/12.2654741

KEYWORDS: Stereoscopy, 3D image processing, Nanoparticles, Luminescence, Gold, Scattering, Light scattering, Ultrasonography, Signal to noise ratio, Signal generators

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SPIE Journal Paper | 13 March 2020 Open Access

Spontaneous loss versus stimulation gain in pump-probe microscopy: a proof of concept demonstration

Subir Das, Khalil Ur Rehman, Guan-Yu Zhuo, Fu-Jen Kao

JBO, Vol. 25, Issue 03, 036501, (March 2020) https://doi.org/10.1117/12.10.1117/1.JBO.25.3.036501

KEYWORDS: Laser beam diagnostics, Seaborgium, Signal detection, Microscopy, Luminescence, Signal to noise ratio, Modulation, Sensors, Stimulated emission depletion microscopy, Photodetectors

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Significance: The large background, narrow dynamic range, and detector saturation have been the common limiting factors in stimulated emission (SE)-based pump-probe microscopy, attributed to the very small signal overriding the very intense laser probe beam. To better differentiate the signal of interest from the background, lock-in detection is used to measure the fluorescence quenching, which is termed spontaneous loss (SL). The advantages are manifold. The spontaneous fluorescence signal can be well separated from both the pump and the probe beams with filters, thus eliminating the background, enlarging the dynamic range, and avoiding the saturation of the detector. Aim: We propose and demonstrate an integrated pump-probe microscopy technique based on lock-in detection for background removal and dynamic range enhancement through SL detection. Approach: The experimental setup is configured with a pulsed diode laser at a wavelength λpu = 635 nm, acting as a pump (excitation) and a mode-locked Ti:sapphire laser at a central wavelength λpr = 780 nm, serving as the probe beam (stimulation). Both pulse trains are temporally synchronized through high precision delay control by adjusting the length of the triggering cables. The pump and probe beams are alternatively modulated at different frequencies f1 and f2 to extract the stimulated gain (SG) and SL signal. Results: SG signal shows saturation due to the irradiation of the intense probe beam onto the photodetector. However, the detector saturation does not occur at high probe beam power for SL detection. The fluorescence lifetime images are acquired with reduced background. The theoretical signal-to-noise ratios for SG and SL are also estimated by photon statistics. Conclusion: We have confirmed that the detection of SL allows the elimination of the large background without photodetector saturation, which commonly exists in SG configuration. This modality would allow unprecedented manipulation and investigation of fluorophores in fluorescence imaging.

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Proceedings Article | 9 March 2020 Presentation

Synchronized subharmonic modulation in stimulated emission microscopy (Conference Presentation)

Fu-Jen Kao

Proceedings Volume 11244, 112441E (2020) https://doi.org/10.1117/12.2544936

KEYWORDS: Modulation, Microscopy, Laser beam diagnostics, Sensors, Signal detection, Confocal microscopy, Signal to noise ratio, Absorption, Image resolution, Luminescence

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Proceedings Article | 23 February 2018 Paper

Stimulated emission and spontaneous loss pump-probe microscopy for background removal

Subir Das, Bo-Wei Ho, Fu-Jen Kao

Proceedings Volume 10498, 104982C (2018) https://doi.org/10.1117/12.2284396

KEYWORDS: Modulation, Microscopy, Semiconductor lasers, Signal to noise ratio, Multiphoton microscopy

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Proceedings Article | 18 April 2017 Paper

Determination of three-dimensional molecular orientation of type-I collagen by circularly-polarized second harmonic generation imaging

Guan-Yu Zhuo, Wei-Han Hung, Fu-Jen Kao

Proceedings Volume 10251, 102511K (2017) https://doi.org/10.1117/12.2269427

KEYWORDS: Second-harmonic generation, Polarization, Tissues, Molecules, Biomedical optics, Skin, Collagen, Harmonic generation, 3D image processing, Microscopy

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Proceedings Article | 9 March 2015 Paper

Optical coherence detection with stimulated emission: a feasibility study

Chun-hui Yu, Shen-Shou Chung, Wen-Chuan Kuo, Fu-Jen Kao

Proceedings Volume 9330, 93301G (2015) https://doi.org/10.1117/12.2077970

KEYWORDS: Optical coherence tomography, Luminescence, Interferometry, Coherence (optics), Photodetectors, Light sources, Signal detection, Scattering, Mirrors, Laser beam diagnostics

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SPIE Journal Paper | 7 October 2014 Open Access

Compact light-emitting diode lighting ring for video-assisted thoracic surgery

Ming-Kuan Lu, Feng-Chen Chang, Wen-Zhe Wang, Chih-Cheng Hsieh, Fu-Jen Kao

JBO, Vol. 19, Issue 10, 105004, (October 2014) https://doi.org/10.1117/12.10.1117/1.JBO.19.10.105004

KEYWORDS: Light emitting diodes, LED lighting, Light sources and illumination, Surgery, Endoscopes, Light sources, Chest, Fiber couplers, Solids, Endoscopy

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Proceedings Article | 28 February 2014 Paper

Multiphoton microscopy for skin wound healing study in terms of cellular metabolism and collagen regeneration

Gitanjal Deka, Kazunori Okano, Wei-Wen Wu, Fu-Jen Kao

Proceedings Volume 8948, 894820 (2014) https://doi.org/10.1117/12.2038472

KEYWORDS: Collagen, Wound healing, Skin, Second-harmonic generation, Anisotropy, Fluorescence lifetime imaging, Biopsy, Multiphoton microscopy, Tissues, Proteins

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Proceedings Article | 28 February 2014 Paper

Enhancing stimulated emission-based fluorescence detection with interferometric setup

Shen-Shou Max Chung, Jia-Hui Deng, Po-Lin Lin, Fu-Jen Kao

Proceedings Volume 8948, 89481T (2014) https://doi.org/10.1117/12.2042085

KEYWORDS: Laser beam diagnostics, Destructive interference, Interferometry, Signal detection, Luminescence, Fluorescence lifetime imaging, Mirrors, Picosecond phenomena, Fluorescence spectroscopy, Microscopy

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Proceedings Article | 28 February 2014 Paper

In pixel analysis of molecular structure with Stokes vector resolved second harmonic generation microscopy

Nirmal Mazumder, Lu Yun Xiang, Jianjun Qiu, Fu-Jen Kao

Proceedings Volume 8948, 894822 (2014) https://doi.org/10.1117/12.2036651

KEYWORDS: Polarization, Second-harmonic generation, Collagen, Polarimetry, Microscopy, Molecules, Calibration, Photon counting, Harmonic generation, Nonlinear optics

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SPIE Journal Paper | 24 January 2014 Open Access

Special Section Guest Editorial: Advanced Biomedical Imaging and Sensing

Chi-Kuang Sun, Arthur Chiou, Fu-Jen Kao, Chien Chou, Chen-Yuan Dong

JBO, Vol. 19, Issue 01, 011001, (January 2014) https://doi.org/10.1117/12.10.1117/1.JBO.19.1.011001

KEYWORDS: Biomedical optics, Biosensing, Photonics, Medicine, Raman spectroscopy, Sun, Physics, Molecular electronics, Molecular imaging, Yeast

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SPIE Journal Paper | 19 August 2013 Open Access

Dynamic photopatterning of cells in situ by Q-switched neodymium-doped yttrium ortho-vanadate laser

Gitanjal Deka, Kazunori Okano, Fu-Jen Kao

JBO, Vol. 19, Issue 01, 011012, (August 2013) https://doi.org/10.1117/12.10.1117/1.JBO.19.1.011012

KEYWORDS: Gold, Polymers, Laser engraving, Laser ablation, Coating, Q switched lasers, Transducers, Adhesives, Neodymium, Glasses

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Proceedings Article | 22 February 2013 Paper

Imaging molecular structure with Stokes-polarimeter based second harmonic generation microscopy

Nirmal Mazumder, Jianjun Qiu, Chih-Wei Hu, Fu-Jen Kao

Proceedings Volume 8588, 858823 (2013) https://doi.org/10.1117/12.2003894

KEYWORDS: Polarization, Second-harmonic generation, Collagen, Signal detection, Microscopy, Polarimetry, Harmonic generation, Molecules, Anisotropy, Photon counting

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Proceedings Article | 22 February 2013 Paper

Fluorescence lifetime imaging with pulsed diode laser enabled stimulated emission

Jianhong Ge, Yixin Wang, Cuifang Kuang, Shin-Shian Lee, Nirmal Mazumder, Fu-Jen Kao

Proceedings Volume 8588, 858832 (2013) https://doi.org/10.1117/12.2009387

KEYWORDS: Fluorescence lifetime imaging, Semiconductor lasers, Luminescence, Modulation, Polarization, Light sources, Sensors, Objectives, Control systems, Photodiodes

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SPIE Journal Paper | 18 December 2012 Open Access

In vivo wound healing diagnosis with second harmonic and fluorescence lifetime imaging

Gitanjal Deka, Wei-Wen Wu, Fu-Jen Kao

JBO, Vol. 18, Issue 06, 061222, (December 2012) https://doi.org/10.1117/12.10.1117/1.JBO.18.6.061222

KEYWORDS: Wound healing, Collagen, Skin, Second-harmonic generation, Fluorescence lifetime imaging, Tissues, In vivo imaging, Signal detection, Proteins, Microscopy

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SPIE Journal Paper | 21 May 2012 Open Access

Metabolism of HeLa cells revealed through autofluorescence lifetime upon infection with enterohemorrhagic Escherichia coli

Tatyana Buryakina, Pin-Tzu Su, Wan-Jr Syu, C. Allen Chang, Hsui-Fang Fan, Fu-Jen Kao

JBO, Vol. 17, Issue 10, 101503, (May 2012) https://doi.org/10.1117/12.10.1117/1.JBO.17.10.101503

KEYWORDS: Cell death, Luminescence, Fluorescence lifetime imaging, Mode conditioning cables, Picosecond phenomena, Proteins, Bacteria, Molecules, Acquisition tracking and pointing, Pathogens

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Proceedings Article | 13 February 2012 Paper

Stokes vector formalism based second harmonic generation microscopy

Jianjun Qiu, Nirmal Mazumder, Han-Ruei Tsai, Chih-Wei Hu, Fu-Jen Kao

Proceedings Volume 8228, 82280C (2012) https://doi.org/10.1117/12.907199

KEYWORDS: Polarization, Second-harmonic generation, Collagen, Microscopy, Harmonic generation, Biomedical optics, Microscopes, Birefringence, Beam splitters, Laser scanners

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Proceedings Article | 9 February 2012 Paper

Long-distance fluorescence lifetime imaging with stimulated emission and electronic time delay

Po-Yen Lin, Shin-Shian Lee, Chia-Seng Chang, Fu-Jen Kao

Proceedings Volume 8226, 82262T (2012) https://doi.org/10.1117/12.907632

KEYWORDS: Luminescence, Imaging systems, Fluorescence lifetime imaging, Signal detection, Fluorescence spectroscopy, Photons, Spatial coherence, Photodiodes, Molecules, Temporal resolution

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SPIE Journal Paper | 6 February 2012 Open Access

Long-distance fluorescence lifetime imaging using stimulated emission

Thilo Dellwig, Po-Yen Lin, Fu-Jen Kao

JBO, Vol. 17, Issue 1, 011009, (February 2012) https://doi.org/10.1117/12.10.1117/1.JBO.17.1.011009

KEYWORDS: Luminescence, Fluorescence lifetime imaging, Biomedical optics, Light sources, Indocyanine green, Molecules, Sensors, Modulation, Rhodamine, Signal to noise ratio

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SPIE Journal Paper | 1 February 2011 Open Access

Forward-collected simultaneous fluorescence lifetime imaging and coherent anti-Stokes Raman scattering microscopy

Aaron Slepkov, Andrew Ridsdale, Adrian Pegoraro, Douglas Moffatt, John Pezacki, Albert Stolow, Huei-Ning Wan, Ming-Hao Wang, Fu-Jen Kao

JBO, Vol. 16, Issue 02, 021103, (February 2011) https://doi.org/10.1117/12.10.1117/1.3490641

KEYWORDS: Fluorescence lifetime imaging, Microscopes, Multimode fibers, Microscopy, Picosecond phenomena, CARS tomography, Sensors, Fiber couplers, Signal detection, Photons

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Proceedings Article | 18 August 2010 Paper

Assessment of ESD robustness in high power light emitting diodes

Shih-Chun Yang, Pang Lin, Han-Kuei Fu, Chien-Ping Wang, Tzung-Te Chen, An-Tse Lee, Sheng-Bang Huang, Pei-Ting Chou, Wei Wang, Fu-Jen Kao

Proceedings Volume 7784, 778419 (2010) https://doi.org/10.1117/12.860322

KEYWORDS: Light emitting diodes, Electroluminescence, Transmission electron microscopy, Failure analysis, Sapphire, Gallium nitride, Scanning electron microscopy, Diodes, Instrument modeling, Electronics

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Proceedings Article | 12 February 2010 Paper

Smart windows with functions of reflective display and indoor temperature-control

I-Hui Lee, Yu-Ching Chao, Chih-Cheng Hsu, Liang-Chao Chang, Tien-Lung Chiu, Jiunn-Yih Lee, Fu-Jen Kao, Chih-Kung Lee, Jiun-Haw Lee

Proceedings Volume 7618, 761816 (2010) https://doi.org/10.1117/12.839815

KEYWORDS: Infrared radiation, Reflectivity, Visible radiation, Liquid crystals, Reflective displays, Polymers, Scattering, Refractive index, Transmittance, Light scattering

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SPIE Journal Paper | 1 January 2010 Open Access

Fluorescence lifetime dynamics of enhanced green fluorescent protein in protein aggregates with expanded polyglutamine

Vladimir Ghukasyan, Chih-Chun Hsu, Chia-Rung Liu, Fu-Jen Kao, Tzhu-Hao Cheng

JBO, Vol. 15, Issue 01, 016008, (January 2010) https://doi.org/10.1117/12.10.1117/1.3290821

KEYWORDS: Luminescence, Proteins, Green fluorescent protein, Molecules, Refractive index, Anisotropy, Fluorescence resonance energy transfer, Molecular aggregates, Fluorescence lifetime imaging, Yeast

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Proceedings Article | 25 February 2009 Paper

Fluorescence lifetime dynamics of eGFP in protein aggregates with expanded polyQ

Vladimir Ghukasyan, Chih-Chun Hsu, Chia-Rung Liu, Fu-Jen Kao, Tzu-Hao Cheng

Proceedings Volume 7183, 718327 (2009) https://doi.org/10.1117/12.809403

KEYWORDS: Proteins, Luminescence, Yeast, Green fluorescent protein, Picosecond phenomena, Chromophores, Refractive index, Cell death, Data modeling, Absorption

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Proceedings Article | 13 February 2009 Paper

Imaging dental sections with polarization-resolved SHG and time-resolved autofluorescence

Jun Huang Chen, Po-Yen Lin, Stephen C. Hsu, Fu-Jen Kao

Proceedings Volume 7183, 71831N (2009) https://doi.org/10.1117/12.808524

KEYWORDS: Collagen, Polarization, Luminescence, Tissues, Microscopy, Teeth, Second-harmonic generation, Fluorescence lifetime imaging, Crystals, Sapphire lasers

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Proceedings Article | 13 February 2009 Paper

Metabolic mapping of cell culture growth by NADH fluorescence lifetime imaging

Vladimir Ghukasyan, Tatyana Buryakina, Fu-Jen Kao

Proceedings Volume 7183, 718309 (2009) https://doi.org/10.1117/12.809840

KEYWORDS: Luminescence, Fluorescence lifetime imaging, Data modeling, Picosecond phenomena, Mode conditioning cables, Microscopy, Molecules, Optical filters, Diffusion, Cellular energetics

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SPIE Journal Paper | 1 September 2008 Open Access

Differentiation of apoptosis from necrosis by dynamic changes of reduced nicotinamide adenine dinucleotide fluorescence lifetime in live cells

Hsing-Wen Wang, Vladimir Ghukasyan, Chien-Tsun Chen, Yau-Huei Wei, Han-Wen Guo, Jia-Sin Yu, Fu-Jen Kao

JBO, Vol. 13, Issue 05, 054011, (September 2008) https://doi.org/10.1117/12.10.1117/1.2975831

KEYWORDS: Cell death, Luminescence, Picosecond phenomena, Control systems, Fluorescence lifetime imaging, Photon counting, Data acquisition, Data modeling, Acquisition tracking and pointing, Ultrasonography

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SPIE Journal Paper | 1 September 2008 Open Access

Reduced nicotinamide adenine dinucleotide fluorescence lifetime separates human mesenchymal stem cells from differentiated progenies

Han-Wen Guo, Chien-Tsun Chen, Yau-Huei Wei, Oscar Lee, Vladimir Ghukasyan, Fu-Jen Kao, Hsing-Wen Wang

JBO, Vol. 13, Issue 05, 050505, (September 2008) https://doi.org/10.1117/12.10.1117/1.2990752

KEYWORDS: Luminescence, Stem cells, Picosecond phenomena, Mode conditioning cables, Acquisition tracking and pointing, In vivo imaging, Fluorescence lifetime imaging, Solids, Biomedical optics, Molecular biology

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Proceedings Article | 2 May 2008 Paper

Biophotonic applications of optical communication devices

Gerd Keiser, Fu-Jen Kao

Proceedings Volume 6991, 69911E (2008) https://doi.org/10.1117/12.779945

KEYWORDS: Biomedical optics, Tissue optics, Waveguides, Optical components, Optical fibers, Telecommunications, Fiber Bragg gratings, Optical filters, Thin films, Ultraviolet radiation

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Proceedings Article | 15 February 2008 Paper

Characterization of the NADH lifetime at different cell densities in a culture

Vladimir Ghukasyan, Fu-Jen Kao

Proceedings Volume 6860, 68602B (2008) https://doi.org/10.1117/12.791153

KEYWORDS: Luminescence, Picosecond phenomena, Data modeling, Mode conditioning cables, Diagnostics, Proteins, Fluorescence lifetime imaging, Photon counting, Microscopes, Molecules

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SPIE Journal Paper | 1 March 2007 Open Access

Application of fluorescence resonance energy transfer resolved by fluorescence lifetime imaging microscopy for the detection of enterovirus 71 infection in cells

Vladimir Gukassyan, Yueh-Ying Hsu, Szu-Hao Kung, Fu-Jen Kao

JBO, Vol. 12, Issue 02, 024016, (March 2007) https://doi.org/10.1117/12.10.1117/1.2718582

KEYWORDS: Fluorescence resonance energy transfer, Fluorescence lifetime imaging, Microscopy, Cell death, Luminescence, Proteins, Molecules, Data modeling, RGB color model, Green fluorescent protein

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Proceedings Article | 7 December 2006 Paper

Cellular vitality of PC12 cells revealed through auto-fluorescence induced by two-photon excitation

Elena Perevedentseva, Artashes Karmenyan, Fu-Jen Kao

Proceedings Volume 5973, 597311 (2006) https://doi.org/10.1117/12.640220

KEYWORDS: Luminescence, Laser irradiation, Optical tweezers, Near infrared, Microscopy, Mode conditioning cables, Fluorescence spectroscopy, Spectroscopy, Laser scanners, Femtosecond phenomena

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Proceedings Article | 18 January 2005 Paper

Harmonic generation microscopy of dental sections

Fu-Jen Kao, Chin-Ying Hsu

Proceedings Volume 5630, (2005) https://doi.org/10.1117/12.577285

KEYWORDS: Second-harmonic generation, Harmonic generation, Collagen, Microscopy, Optical parametric oscillators, Sapphire lasers, Biomedical optics, Luminescence, Teeth, Phase matching

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Proceedings Article | 11 January 2005 Paper

Laser scanning microscopy as a versatile platform: imaging based on nonlinear and ultrafast effects

Fu-Jen Kao

Proceedings Volume 5642, (2005) https://doi.org/10.1117/12.569454

KEYWORDS: Second-harmonic generation, Signal detection, Microscopy, Signal processing, Collagen, Laser scanners, Confocal microscopy, Modulation, Ultrafast lasers, Harmonic generation

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Proceedings Article | 21 June 2004 Paper

Use of optical parametric oscillator in scanning optical microscopy

Fu-Jen Kao

Proceedings Volume 5323, (2004) https://doi.org/10.1117/12.528661

KEYWORDS: Optical parametric oscillators, Luminescence, Second-harmonic generation, Harmonic generation, Ultraviolet radiation, Sapphire lasers, Collagen, Microscopy, Optical microscopy, Phase matching

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Proceedings Article | 16 June 2004 Paper

Optical biosensor based on localized surface plasmon resonance with high spatial resolution

Xin Hong, Fu-Jen Kao

Proceedings Volume 5327, (2004) https://doi.org/10.1117/12.525962

KEYWORDS: Spatial resolution, Absorption, Objectives, Gold, Nanoparticles, Sensors, Surface plasmons, Biosensing, Light sources, Optical fibers

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Proceedings Article | 8 June 2004 Paper

Optical beam induced current microscopy at DC and radio frequency

Fu-Jen Kao

Proceedings Volume 5353, (2004) https://doi.org/10.1117/12.528592

KEYWORDS: Photodiodes, Radio optics, Semiconductors, Active optics, Mode locking, Electrodes, Diffusion, Near field optics, Spatial resolution, Pulsed laser operation

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Proceedings Article | 4 December 2003 Paper

The use of advanced light source and signal processing in scanning optical microscopy

Fu-Jen Kao

Proceedings Volume 5255, (2003) https://doi.org/10.1117/12.546235

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Proceedings Article | 24 April 2001 Paper

Nonlinear multimodality spectromicroscopy: multiphoton fluorescence, SHG, and THG of biological specimen

Ping Cheng, Chi-Kuang Sun, Bai-Ling Lin, Fu-Jen Kao, Shi-Wei Chu

Proceedings Volume 4262, (2001) https://doi.org/10.1117/12.424541

KEYWORDS: Second-harmonic generation, Luminescence, Multiphoton fluorescence microscopy, Signal attenuation, Microscopy, Nonlinear optics, Signal detection, Visible radiation, Sapphire lasers, Multiphoton microscopy

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