• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.616-619
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• 2003

Photochemical and photothermal effects have correlation with each other and depend on laser wavelength. Multi-scanning laser ablation process of polymer with DPSS(Diode Pumped Solid State) 3rd harmonic Nd:YVO$_4$ laser with wavelength of 355nm is applied to fabricate three-dimensional micro shape. The DPSSL photomachining system can rapidly and cheaply fabricate 2D pattern or 3D shape with high efficiency because we only use CAD/CAM software and precision stages instead of complex projection mask. Photomachinability of polymer is highly influenced by laser wavelength and its own chemical structure. So the optical characteristics of polymers for 355nm laser source is investigated by experimentally and theoretically.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.53 no.1
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• pp.30-35
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• 2004

We have carried out a basic experiment in order to develope a super high-resolution optical microscope which transcend the limitation of diffraction and the wavelength of lightwave. The image of this scope is composed by measuring the evanescent wave which is localized on the surface of the testing materials. A detecting probe was fabricated with a single mode optical fiber to be sharpened by the chemical etching, and drived by PZT. The standing wave of $0.33\mu\textrm{m}$ wavelength evanescent wave which was generated from the $0.78\mu\textrm{m}$-wavelength semiconductor laser was detected by the $0.5\mu\textrm{m}$-thickness optical fiber probe.

• Korean Journal of Remote Sensing
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• v.36 no.6_3
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• pp.1681-1690
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• 2020

A scanning lidar system has been developed. The system has two wavelength observation channels of 532 and 1064 nm and is capable of 360-degree horizontal scanning observation. In addition, an analysis method that can classify the measured particle as an indicator of coarse-mode particle (PM2.5-10) and an indicator of fine-mode particles (PM2.5) and calculate the mass concentration of each has been developed by using the backscatter coefficient at two wavelengths. It was applied to the data calculated by observation. The mass concentrations of PM10 and PM2.5, which showed a distribution of 22-110 ㎍/㎥ and 7-78 ㎍/㎥, respectively, were successfully calculated in the Ulsan Onsan Industrial Complex using the developed scanning lidar system. The analyzed results showed similar values to the mass concentrations measured on the ground around the lidar observation area, and it was confirmed that high concentrations of 80-110 ㎍/㎥ and 60-78 ㎍/㎥ were measured at points discharged from factories, respectively.

• Journal of Korea Society of Digital Industry and Information Management
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• v.10 no.2
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• pp.13-20
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• 2014

In this paper, we implemented the object scanning with nxtOSEK which is an open source platform. nxtOSEK consists of device driver of leJOS NXJ C/Assembly source code, TOPPERS/ATK(Automotive real time Kernel) and TOPPERS/JSP Real-Time Operating System source code that includes ARM7 specific porting part, and glue code make them work together. nxtOSEK can provide ANSI C by using GCC tool chain and C API and apply for real-time multi tasking features. We experimented the 3D scanning with ultra sonic and laser sensor which are made directly by laser module diode and experimented the measurement of scanning the object by knowing x, y, and z coordinates for every points that it scans. In this paper, the laser module is the dimension of $6{\times}10[mm]$ requiring 5volts/5[mW], and used the laser light of wavelength in the 650[nm] range. For detecting the object, we used the beacon detection algorithm and as the laser light swept the objects, the photodiode monitored the ambient light at interval of 10[ms] which is called a real time. We communicated the 3D scanning platform via bluetooth protocol with host platform and the results are displayed via DPlot graphic tool. And therefore we enhanced the functionality of the 3D scanner for identifying the image scanning with laser sensor modules compared to ultra sonic sensor.

• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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• 2001.06a
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• pp.1123-1123
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• 2001

In recent years, a miniature spectrometer has been extensively developed due to the marriage of fiber optics and semiconductor detector array. This type of miniature spectrometer has advantages of low price and robustness due to the capability of mass production and no moving parts are required such as lenses, mirrors and scanning monochromator. These systems are ideal for use in teaching labs, process monitoring and field analyses. A portable near infrared (NIR) system has been developed for qualitative and quantitative analysis. This system includes a tungsten halogen lamp for light source, a fiber optics connected a light source, and a sample module to the microspectrometer, The size of spectrometer can be as small as 2.5 cm x 1.5 cm x 0.1 cm. Wavelength ranges can be chosen as 360-800 nm, 800-1100 nm and 1100-1900 nm depending on the type of detector. The software consists of various tools for multivariate analysis and pattern recognition techniques. To evaluate the system, long and short-term stability, wavelength accuracy, and stray light have been investigated and compared with conventional scanning type NIR spectrometer. This developed system can be sufficiently used for quantitative and qualitative analysis for various samples such as agricultural product, herbal medicine, food, petroleum, and pharmaceuticals, etc.

• Journal of the Korean Society for Precision Engineering
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• v.31 no.3
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• pp.199-205
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• 2014

We propose a new variant of lateral shearing interferometer with a tunable laser source that enables 3D surface profile measurements of freeform optics with high speed, high vertical resolution, large departure, and large field-of-view. We have verified the proposed technique by comparing our measurement result with that of an existing technique and measuring a representative sample of freeform optics. Moreover, we propose a new algorithm that is able to compensate the rotational inaccuracy.

• Journal of Biomedical Engineering Research
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• v.17 no.4
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• pp.479-490
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• 1996

To utilize collagen as an implantable biomateriall the mcct widely used bovine skin origin Type I collagen was investigated Pepsin treated, Type I atelocollagen was extracted and crosslinked by the ultraviolet(W) ray with wavelength of 254nm or by various concentrations of glutaraldehyde to produce collagen membranes. The crosslink rates of the specimens were observed by a polarized light microscope, a scanning electron microscope, and a Fourier transform infrared (FT-lR) spectrometer. The followings are concluded 1. The collagen membranes produced by both 2.5% glutaraldehyde solution and 254nm UV ray irra- diation demonstrated similar morphologies on polarized light microscopic and scanning electron microscopic views. 2. The chemical structures of the crosslinked membranes by glutaraldehyde over 2.5% in concentrations revealed similar intensities to that of the UV ray irradiated one in FT-lR investigation. 3. To obtain optimal croulink in bovine stalin origin Type I atelocollagen, 2.5% glutaraldehyde solution or UV ray irradiation with 254nm wavelength is acceptable.

• Transactions on Electrical and Electronic Materials
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• v.14 no.2
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• pp.59-62
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• 2013

At an infra-red (IR) wavelength of 1,064 nm, a diode-pumped Q-switched $Nd:YVO_4$ laser was used for the direct patterning of various transparent conductive oxide (TCO) thin films on glass substrate. With various laser beam conditions, the laser ablation results showed that the indium tin oxide (ITO) film was removed completely. In contrast, zinc oxide (ZnO) film was not etched for any laser beam conditions and indium gallium zinc oxide (IGZO) was only ablated with a low scanning speed. The difference in laser ablation is thought to be due to the crystal structures and the coefficient of thermal expansion (CTE) of ITO, IGZO, and ZnO. The width of the laser-patterned grooves was dependent on the film materials, the repetition rate, and the scanning speed of the laser beam.

• Current Optics and Photonics
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• v.3 no.1
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• pp.16-21
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• 2019

We present a broad-bandwidth comb-spacing-swept source (CSWS) based on a differential polarization delay line (DPDL) for interferometric three-dimensional (3D) imaging. The comb spacing of the CSWS is repeatedly swept by the tunable DPDL in the multiwavelength source to provide depth-scanning optical coherence tomography (OCT). As the polarization differential delay of the DPDL is tuned from 5 to 15 ps, the comb spacing along the wavelength continuously varies from 1.6 to 0.53 nm, respectively. The wavelength range of various semiconductor optical amplifiers and the cavity feedback ratio of the tunable fiber coupler are experimentally selected to obtain optimal conditions for a broader 3-dB bandwidth of the multiwavelength spectrum and thus provide a higher axial resolution of $35{\mu}m$ in interferometric OCT imaging. The proposed CSWS-OCT has a simple imaging interferometer configuration without reference-path scanning and a simple imaging process without the complex Fourier transform. 3D surface images of a via-hole structure on a printed circuit board and the top surface of a coin were acquired.

• Korean Journal of Optics and Photonics
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• v.10 no.3
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• pp.201-207
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• 1999

The fiber-optical confocal scanning interference microscope with a simple configuration was constructed with a 4-port fiber-optic coupler, and the new method based on the phase shifting method was proposed for surface profiling by the system. In the method, the height of a specimen was determined from the phase of confocal beam. It was verified experimentally that the method was applicable to even the confocal interference microscope with a long-wavelength source and a low NA objective, and that the scanning time could be drastically reduced compared with the conventional method. Finally, it was found that our method is less sensitive to the variation of surface reflectivity than the conventional method.