scholarly journals Investigation and Improvement of Thermal Stability of a Chromatic Confocal Probe with a Mode-Locked Femtosecond Laser Source

2019 ◽  
Vol 9 (19) ◽  
pp. 4084 ◽  
Author(s):  
Ryo Sato ◽  
Yuki Shimizu ◽  
Chong Chen ◽  
Hiraku Matsukuma ◽  
Wei Gao
Keyword(s):  
Thermal Stability ◽  
Thermal Expansion ◽  
Femtosecond Laser ◽  
Thermal Instability ◽  
Theoretical Calculations ◽  
Surface Profile ◽  
Laser Source ◽  
Profile Measurement ◽  
Chromatic Confocal Probe ◽  
Thermal Stability Of

An intentional investigation on the thermal stability of a mode-locked femtosecond laser chromatic confocal probe, which is a critical issue for the probe to be applied for long-term displacement measurement or surface profile measurement requiring long-time scanning, is carried out. At first, the thermal instability of the first prototype measurement setup is evaluated in experiments where the existence of a considerably large thermal instability is confirmed. Then the possible reasons for the thermal instability of the measurement setup are analyzed quantitatively, such as the thermal instability of the refractive index of the confocal lens and the thermal expansion of mechanical jigs employed in the probe. It is verified that most of the thermal instability of the measurement setup is caused by the thermal expansion of mechanical jigs in the probe. For the improvement of the thermal stability of the probe, it is necessary to employ a low thermal expansion material for the mechanical jigs in the measurement setup and to shorten the optical path length of the laser beam. Based on the analysis result, a second prototype probe is newly designed and constructed. The improved thermal stability of the second prototype probe is verified through theoretical calculations and experiments.

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.

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.

scholarly journals A Method for Expansion of Z-Directional Measurement Range in a Mode-Locked Femtosecond Laser Chromatic Confocal Probe

2019 ◽  
Vol 9 (3) ◽  
pp. 454 ◽  
Author(s):  
Chong Chen ◽  
Ryo Sato ◽  
Yuki Shimizu ◽  
Taku Nakamura ◽  
Hiraku Matsukuma ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Femtosecond Laser ◽  
Intensity Ratio ◽  
Theoretical Calculations ◽  
Expansion Method ◽  
Measurement Range ◽  
Laser Source ◽  
Peak Wavelength ◽  
Dual Detector ◽  
Chromatic Confocal Probe

A method is proposed to expand the Z-directional measurement range of a fiber-based dual-detector chromatic confocal probe with a mode-locked femtosecond laser source. In the dual-detector chromatic confocal probe, the Z-directional displacement of a measurement target is derived from the peak wavelength in the normalized intensity ratio from the two light intensities obtained by the two identical fiber detectors. In this paper, a new method utilizing the main-lobe and side-lobes of axial responses acquired from both the normalized intensity ratio Ia and the invert normalized intensity ratio In, which is the inverse of Ia, is proposed to obtain the seamless relationship between the peak wavelength and the Z-directional displacement of a measurement target. Theoretical calculations and experimental investigation are carried out to demonstrate the feasibility of the proposed measurement range expansion method.

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

Optical and thermal stability of Ge-as-Se chalcogenide glasses for femtosecond laser writing

2018 ◽  
Vol 85 ◽  
pp. 220-225 ◽  
Author(s):  
Liang Zhu ◽  
Dandan Yang ◽  
Leilei Wang ◽  
Jianghui Zeng ◽  
Qian Zhang ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Femtosecond Laser ◽  
Chalcogenide Glasses ◽  
Laser Writing ◽  
Thermal Stability Of

scholarly journals Measurement Range Expansion of Chromatic Confocal Probe with Supercontinuum Light Source

2021 ◽  
Vol 15 (4) ◽  
pp. 529-536
Author(s):  
Hiraku Matsukuma ◽  
◽  
Ryo Sato ◽  
Yuki Shimizu ◽  
Wei Gao
Keyword(s):  
Light Source ◽  
Range Expansion ◽  
Wide Spectrum ◽  
Surface Profile ◽  
Measurement Range ◽  
Detection Sensitivity ◽  
Laser Source ◽  
Supercontinuum Light Source ◽  
Chromatic Confocal Probe ◽  
Measurable Range

Confocal probes have been widely adopted in various industries owing to their depth-sectioning effects. A dual-detector differential chromatic confocal probe using a mode-locked femtosecond laser source is proposed herein, and the measurement range expansion of the probe using a supercontinuum light source is discussed. Supercontinuum light has an extremely wide spectrum. A simulation based on wave optics is performed to evaluate the detection sensitivity and measurable range by considering the chromatic aberration of the lens materials. Additionally, an experimental setup is constructed using a supercontinuum light source, and its feasibility is validated. A measurable range of 200 μm is adopted in the experiment, and three-dimensional surface profile measurements are performed. However, the developed confocal probe has not been used for surface topography measurements. Experiments are conducted to verify the performance of the developed probe.

Effect of metal catalyst thermal expansion on thermal stability of synthetic diamonds

2012 ◽  
Vol 53 (1) ◽  
pp. 409-415 ◽  
Author(s):  
Mykola V. Novikov ◽  
Anatoliy L. Maystrenko ◽  
Volodymyr I. Kushch
Keyword(s):  
Thermal Stability ◽  
Thermal Expansion ◽  
Metal Catalyst ◽  
Synthetic Diamonds ◽  
Thermal Stability Of
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