• Photonics industry news
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• s.5
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• pp.70-75
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• 2001

• The Optical Journal
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• s.129
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• pp.48-52
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• 2010

Maiman이 루비레이저 발진에 성공하고 나서 50년, 고출력레이저는 멈추지 않고 진보를 계속하고 있다. 그 결과 광에는 한계가 없다는 물리학의 본질에 뿌리내린 한계도전이 현실로 다가왔다. 고출력레이저의 응용분야는 원자와 분자를 광(光)전계 만으로 전리, 파괴할 뿐만 아니라 전자속도를 광속까지 가속시키는 상대론광학, 그것에 의한 새로운 입자가속기와 레이저에 의한 고(高)에너지물리학으로의 전망, 그리고 실험실 우주물리학에 이르기까지 소개했다. 이들 연구에는 각각 획기적인 아이디어와 연구축적이 필요하고, 이후도 끊임없는 노력이 이어질 전망이다. 본고는 <광기술 컨텍트 2010년 1월호> 미래의 광기술 기획특집중 Ueda Ken-ichi(전기통신대학 레이저신세대연구센터)씨가 집필한 '초고출력레이저의 전망'을 전제한 것이며 (주)그린광학의 유정훈 팀장이 번역에 도움을 주었다.

• Korean Journal of Optics and Photonics
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• v.32 no.4
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• pp.147-152
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• 2021

We report high-power continuous-wave operation of a Yb-doped fiber laser at 1070 nm, pumped by high-power laser diodes at 976 nm. Based on theoretical calculation of the stimulated Raman scattering and temperature distribution in the fiber, we construct a bidirectionally pumped Yb-fiberlaser system incorporating a pair of fiber Bragg gratings and a cladding light stripper. The fiber laser yields 3.0 kW of continuous-wave output at 1070 nm in a diffraction-limited beam with M² ≈ 1.26 for 4.1 kW of incident pump power, corresponding to a slope efficiency of 81.5%. The prospects for further power scaling are discussed.

• Journal of the Korean Society of Industry Convergence
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• v.25 no.3
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• pp.365-378
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• 2022

Complete blood cell count(CBC) is a technique that counts leukocytes for each type of blood cell being analyzed. The principle is that laser is incident to ex vivo flowing leukocytes in a microcapillary tube and scattered light occurs by laser and leukocytes. By collecting the scattered light, we can count the types of cells because different cells generate different light-scattering patterns. However, the technique has an intrinsic limitation, scattering pattern is shown in a wide range region in the resulting, which makes it difficult to accurate analyze and use fluorescent dyes. To overcome this limitation, a new design of CBC with a dual laser, which irradiates with orthogonal angles for collecting quad-scattering information was proposed. Before development, the scattering difference depending on wavelength must be investigated to only catch up to the scattered signal by angles. Some studies, which focused on simple particles, have been conducted to theoretically and experimentally investigate different scatterings by wavelength. In this study, we propose an optical system for measuring scattered light and investigate a complex particle. As a result, the green laser made strong scattering signals in both the forward and side direction: 10% and 30%, respectively.

• Journal of the Microelectronics and Packaging Society
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• v.30 no.3
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• pp.102-110
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• 2023

This paper introduces scarf welding process of thin substrates using flexible laser transmission welding (f-LTW) technology. We examined the behavior of tensile strength relative to the scarf angle for flexible applications. Thin plastic substrates with the thickness of less than 100 ㎛ were bonded and a jig to form a slope at the edge of the substrate was developed. By developing the scarf welding process, we successfully created a flexible bonding technology that maintains joint's thickness after the process. The tensile strength of the joint was assessed through uniaxial test, and we found that the tensile strength increases as the slope of bonding interface decreases. By conducting stress analysis at the bonding interface with respect to the slope angle, design factor of bonding structure was investigated. These findings suggest that the tensile strength depends on the geometry of the joint, even under the same process conditions, and highlights the significance of considering the geometry of the joint in welding processes.

• Journal of the Microelectronics and Packaging Society
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• v.30 no.2
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• pp.65-70
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• 2023

Nanoimprint lithography (NIL) has attracted much attention due to its process simplicity, excellent patternability, process scalability, high productivity, and low processing cost for pattern formation. However, the pattern size that can be implemented on metal materials through conventional NIL technologies is generally limited to the micro level. Here, we introduce a novel hard imprint lithography method, extreme-pressure imprint lithography (EPIL), for the direct nano-to-microscale pattern formation on the surfaces of metal substrates with various thicknesses. The EPIL process allows reliable nanoscopic patterning on diverse surfaces, such as polymers, metals, and ceramics, without the use of ultraviolet (UV) light, laser, imprint resist, or electrical pulse. Micro/nano molds fabricated by laser micromachining and conventional photolithography are utilized for the nanopatterning of Al substrates through precise plastic deformation by applying high load or pressure at room temperature. We demonstrate micro/nanoscale pattern formation on the Al substrates with various thicknesses from 20 ㎛ to 100 mm. Moreover, we also show how to obtain controllable pattern structures on the surface of metallic materials via the versatile EPIL technique. We expect that this imprint lithography-based new approach will be applied to other emerging nanofabrication methods for various device applications with complex geometries on the surface of metallic materials.