Fiber-based 1150-nm femtosecond laser source for the label-free virtual optical biopsy (Conference Presentation)

2018 ◽  
Author(s):  
Tzu-Ming Liu ◽  
Jing-Yu Huang ◽  
Lun-Zhang Guo ◽  
Jing-Zun Wang ◽  
Tse-Chung Li ◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Optical Biopsy ◽  
Laser Source ◽  
Label Free

scholarly journals An Optical Frequency Domain Angle Measurement Method Based on Second Harmonic Generation

Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 670
Author(s):  
Wijayanti Dwi Astuti ◽  
Hiraku Matsukuma ◽  
Masaru Nakao ◽  
Kuangyi Li ◽  
Yuki Shimizu ◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Second Harmonic Generation ◽  
Frequency Domain ◽  
Harmonic Generation ◽  
Measurement Method ◽  
Second Harmonic ◽  
Angle Measurement ◽  
Laser Source ◽  
Optical Frequency ◽  
Measurable Range

This paper proposes a new optical angle measurement method in the optical frequency domain based on second harmonic generation with a mode-locked femtosecond laser source by making use of the unique characteristic of the high peak power and wide spectral range of the femtosecond laser pulses. To get a wide measurable range of angle measurement, a theoretical calculation for several nonlinear optical crystals is performed. As a result, LiNbO3 crystal is employed in the proposed method. In the experiment, the validity of the use of a parabolic mirror is also demonstrated, where the chromatic aberration of the focusing beam caused the localization of second harmonic generation in our previous research. Moreover, an experimental demonstration is also carried out for the proposed angle measurement method. The measurable range of 10,000 arc-seconds is achieved.

scholarly journals 1700 nm optical coherence microscopy enables minimally invasive, label-free, in vivo optical biopsy deep in the mouse brain

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Jun Zhu ◽  
Hercules Rezende Freitas ◽  
Izumi Maezawa ◽  
Lee-way Jin ◽  
Vivek J. Srinivasan
Keyword(s):  
Minimally Invasive ◽  
Mouse Brain ◽  
Numerical Aperture ◽  
Optical Biopsy ◽  
Optical Coherence ◽  
Label Free ◽  
Optical Coherence Microscopy ◽  
Minimal Invasiveness ◽  
Cortical Regions

AbstractIn vivo, minimally invasive microscopy in deep cortical and sub-cortical regions of the mouse brain has been challenging. To address this challenge, we present an in vivo high numerical aperture optical coherence microscopy (OCM) approach that fully utilizes the water absorption window around 1700 nm, where ballistic attenuation in the brain is minimized. Key issues, including detector noise, excess light source noise, chromatic dispersion, and the resolution-speckle tradeoff, are analyzed and optimized. Imaging through a thinned-skull preparation that preserves intracranial space, we present volumetric imaging of cytoarchitecture and myeloarchitecture across the entire depth of the mouse neocortex, and some sub-cortical regions. In an Alzheimer’s disease model, we report that findings in superficial and deep cortical layers diverge, highlighting the importance of deep optical biopsy. Compared to other microscopic techniques, our 1700 nm OCM approach achieves a unique combination of intrinsic contrast, minimal invasiveness, and high resolution for deep brain imaging.

A chromatic confocal probe with a mode-locked femtosecond laser source

2018 ◽  
Vol 103 ◽  
pp. 359-366 ◽  
Author(s):  
Xiuguo Chen ◽  
Taku Nakamura ◽  
Yuki Shimizu ◽  
Chong Chen ◽  
Yuan-Liu Chen ◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Laser Source ◽  
Chromatic Confocal Probe

Development of an Optical Angle Sensor With a Mode-Locked Femtosecond Laser Source for Surface Profile Measurement

2020 ◽  
Author(s):  
Yuki Shimizu ◽  
Shota Takazono ◽  
Yuri Kanda ◽  
Hiraku Matsukuma ◽  
Wei Gao ◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Surface Profile ◽  
Single Mode ◽  
Single Mode Fiber ◽  
Laser Source ◽  
Profile Measurement ◽  
Angle Sensor ◽  
Optical Setup ◽  
Optical Modes ◽  
Optical Angle Sensor

Abstract Angle sensors based on the laser autocollimation are often employed to evaluate surface profiles of a target of interest. The authors have developed a femtosecond laser angle sensor, in which a spectrometer or an optical spectrum analyzer with a single-mode fiber is employed as the photodetector for simultaneous capturing of the multiple optical modes. In this paper, the concept of the femtosecond laser angle sensor is applied to evaluate the surface profile of a target of interest. An optical setup is designed in such a way that each mode in the spectrum of the mode-locked femtosecond is utilized as the laser beam to measure the local slope of a measurement target at each different point to evaluate the surface profile. Some basic experiments are carried out by using the developed optical setup with a mode-locked femtosecond laser source to evaluate basic performances of the developed optical setup as an optical angle sensor.

Profile Measurement by Using a Femtosecond Laser Chromatic Confocal Probe

2020 ◽  
Author(s):  
Ryo Sato ◽  
Yuki Shimizu ◽  
Hiraku Matsukuma ◽  
Wei Gao
Keyword(s):  
Thermal Stability ◽  
Femtosecond Laser ◽  
Surface Profile ◽  
Sample Surface ◽  
Measurement Range ◽  
Laser Source ◽  
Profile Measurement ◽  
Experimental Setup ◽  
Chromatic Confocal Probe ◽  
Surface Profile Measurement

Abstract Confocal probes are widely employed in many industrial fields due to the depth-sectioning effect. The author’s group has also proposed a chromatic confocal probe employing a mode-locked femtosecond laser source which can realize an axial resolution of 30 nm and a measurement range of 40 μm Efforts have also been made to improve the thermal stability of the developed femtosecond laser chromatic confocal probe so that the probe can be applied for long-term displacement measurement or surface profile measurement. Meanwhile, surface profile measurement has not been carried out by using the developed femtosecond laser chromatic confocal probe. For the verification of the performance of developed probe in profile measurement, in this paper, an experimental setup is built and a basic experiment is carried out. By using the probe with further improved thermal stability, the measurement of a sample surface profile is carried out. In this paper, the development of the experimental setup with the femtosecond laser chromatic confocal probe, as well as the results of the surface profile measurements, is presented.

Power Ultraviolet Laser Source Based on Photonic Crystal Fiber Femtosecond Laser System

2009 ◽  
Vol 36 (11) ◽  
pp. 2812-2816
Author(s):  
刘华刚 Liu Huagang ◽  
胡明列 Hu Minglie ◽  
刘博文 Liu Bowen ◽  
宋有建 Song Youjian ◽  
柴路 Chai Lu ◽  
...  
Keyword(s):  
Photonic Crystal ◽  
Femtosecond Laser ◽  
Photonic Crystal Fiber ◽  
Laser System ◽  
Laser Source ◽  
Ultraviolet Laser ◽  
Crystal Fiber

scholarly journals Effect of Laser Pulse Overlap and Scanning Line Overlap on Femtosecond Laser-Structured Ti6Al4V Surfaces

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 969 ◽  
Author(s):  
Georg Schnell ◽  
Ulrike Duenow ◽  
Hermann Seitz
Keyword(s):  
Laser Pulse ◽  
Femtosecond Laser ◽  
Surface Topography ◽  
Cell Attachment ◽  
Surface Structures ◽  
Laser Source ◽  
Laser Machining ◽  
Scanning Strategy ◽  
Wide Range ◽  
Scanning Line

Surface structuring is a key factor for the tailoring of proper cell attachment and the improvement of the bone-implant interface anchorage. Femtosecond laser machining is especially suited to the structuring of implants due to the possibility of creating surfaces with a wide variety of nano- and microstructures. To achieve a desired surface topography, different laser structuring parameters can be adjusted. The scanning strategy, or rather the laser pulse overlap and scanning line overlap, affect the surface topography in an essential way, which is demonstrated in this study. Ti6Al4V samples were structured using a 300 fs laser source with a wavelength of 1030 nm. Laser pulse overlap and scanning line overlap were varied between 40% and 90% over a wide range of fluences (F from 0.49 to 12.28 J/cm²), respectively. Four different main types of surface structures were obtained depending on the applied laser parameters: femtosecond laser-induced periodic surface structures (FLIPSS), micrometric ripples (MR), micro-craters, and pillared microstructures. It could also be demonstrated that the exceedance of the strong ablation threshold of Ti6Al4V strongly depends on the scanning strategy. The formation of microstructures can be achieved at lower levels of laser pulse overlap compared to the corresponding value of scanning line overlap due to higher heat accumulation in the irradiated area during laser machining.

scholarly journals Femtosecond laser induced selective etching in fused silica: optimization of the inscription conditions with a high-repetition-rate laser source

2018 ◽  
Vol 26 (23) ◽  
pp. 29669 ◽  
Author(s):  
Jia Qi ◽  
Zhenhua Wang ◽  
Jian Xu ◽  
Zijie Lin ◽  
Xiaolong Li ◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Repetition Rate ◽  
High Repetition Rate ◽  
Fused Silica ◽  
Selective Etching ◽  
Laser Source ◽  
High Repetition
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