게시판
최근논문
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[하이라이트 논문] 한국광학회지 Vol. 36 No. 2 (2025 April)
Wavelength-swept Source-based Wide Line-field Optical Coherence Tomography System
파장가변광원 기반 광폭 선형영역 광결맞음 단층영상 시스템
이승석ㆍ마혜준ㆍ김현성ㆍ최은서†
한국광학회지 Vol. 36 No. 2 (2025 April), pp. 85-93
DOI: https://doi.org/10.3807/KJOP.2025.36.2.085
Fig. 1 Lab-built wavelength-swept light source. The light source comprises two semiconductor optical amplifiers (SOAs), two isolators, a Fabry-Perot (FP) filter,
and an output coupler. SOA2 is employed to amplify the output power emitted from the ring cavity.
Keywords: 대면적, 비주사, 광단층촬영법, 파장가변광원, 광폭 선형영역
OCIS codes: (100.6950) Tomographic image processing; (110.3175) Interferometric imaging; (120.3180) Interferometry
초록
본 논문에서는 전수검사에 활용하기 위해 개발된 line-field optical coherence tomography (LF-OCT) 시스템의 성능을 제시하였다. 광섬유 고리 공진기와 파장가변필터를 이용한 파장가변광원은 중심파장 1330 nm, 파장 반치폭 80 nm, 출력 광세기 90 mW의 특성을 보이며 100 Hz의 반복률로 동작하였다. 총 3장의 렌즈로 구성된 광폭 스캔 렌즈는 폭 100 mm 이하, 200 mm 길이의 선형빔을 발생시킬 수 있었 다. 파장가변광원과 절반 크기로 가공된 광폭 스캔 렌즈를 가지고 마이켈슨 간섭계 형태로 구현된 LF-OCT 시스템은 20 mm의 깊이 분해능과
Abstract
This paper presents the performance of a line-field optical coherence tomography (LF-OCT) system developed for full inspection. A wavelengthswept light source using a fiber ring resonator and a wavelength-tunable filter was operated at a repetition rate of 100 Hz with a center wavelength of 1330 nm, a spectral bandwidth of 80 nm, and an output power of 90 mW. The wide scan lens, designed in three lenses, could generate a line-field beam less than 100 mm wide and 200 mm long. The LF-OCT system implemented in a Michelson interferometer with a wavelength-swept light source and a wide-scan lens fabricated to half its dimension presented an axial resolution of 20 mm and a depth range of 2.84 mm at 3 dB. We could confirm 3 mm imaging depth through gauge block imaging and obtain 100-mm-wide tomographic images of a metal ruler without scanning. By optimizing the implemented LF-OCT, we will be able to demonstrate its utility as an inspection device for real-time, full-scale inspections required in industrial fields.
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[Editor's Pick] Current Optics and Photonics Vol. 9 no. 2 (2025 April)
High-harmonic Generation in van der Waals Two-dimensional Materials
Dasol Kim, Alexis Chacon, and Jonghwan Kim*
Current Optics and Photonics Vol. 9 No. 2 (2025 April), pp. 95-107
DOI: https://doi.org/10.3807/COPP.2025.9.2.95
Fig. 1 Schematics of high-harmonic generation in van der Waals (vdW) 2D materials:
(a) Commonly used vdW 2D materials. (b) Experimental configuration of high-harmonic-generation measurement.
Keywords: High energy photon sources, High harmonic generation, Solid state physics, Strong-field, light-matter interaction, van der Waals 2D materials
OCIS codes: (040.7480) X-rays, soft X-rays, extreme ultraviolet (EUV); (140.0140) Lasers and laser optics; (160.4330) Nonlinear optical materials; (190.0190) Nonlinear optics; (320.0320) Ultrafast optics
Abstract
High-harmonic generation (HHG) in gases has long enabled tabletop access to coherent extreme ultraviolet (XUV) and soft X-ray radiation. More recently HHG has been extended to the solid-state realm, offering potential advantages such as higher conversion efficiency, tunability via band-structure engineering, and integration with photonic devices. Among emerging solid-state platforms, van der Waals (vdW) two-dimensional (2D) materials—e.g., graphene, transition-metal dichalcogenides (TMDs), and black phosphorus—exhibit pronounced quantum confinement, strong excitonic effects, and valleyselective dynamics. These properties yield unique HHG signatures, including polarization dependence, extended harmonic orders, and topological effects. This review summarizes fundamental mechanisms of HHG in vdW 2D materials, key experimental breakthroughs, and state-of-the-art theoretical approaches. We discuss exciton-driven enhancements, Berry-curvature-induced polarization, and device-integration challenges. We also highlight prospective directions, such as advanced ultrafast spectroscopy and applications in attosecond science, underscoring the rich opportunities and persistent challenges in harnessing strong-field light-matter interactions in 2D quantum materials.
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[Editor's Pick] Current Optics and Photonics Vol. 9 no. 1 (2025 February)
Recent Theoretical and Experimental Progress on Boson Sampling
Changhun Oh*
Current Optics and Photonics Vol. 9 No. 1 (2025 Februrary), pp. 1-18
DOI: https://doi.org/10.3807/COPP.2025.9.1.1
Fig. 1 Setup for Fock-state boson sampling. N indistingui shable photons pass through an M-mode interferometer, and then are measured at the output modes on the Fock basis. Reprinted from R. Garcia-Patron et al. Quantum 2019; 3; 169. Copyright © 2019, R. Garcia-Patron et al. [35].
Keywords: Boson sampling, Quantum advantage, Quantum computer, Quantum optics
OCIS codes: (270.0270) Quantum optics; (270.5585) Quantum information and processing; (270.6570) Squeezed states
Abstract
Boson sampling is a restricted model of quantum computation, designed to achieve quantum advantage using nonuniversal quantum systems. By harnessing the quantum interference of indistinguishable bosons (typically photons), it becomes possible to sample from a probability distribution, which is intractable for classical computers. This paper reviews the theoretical foundations of boson sampling and its variations, including Fock-state, scattershot, and Gaussian boson sampling, along with significant experimental progress, from early small-scale demonstrations to large-scale quantum supremacy claims. We further explore classical algorithms for simulating boson sampling, which are crucial for benchmarking the performance of experimental results. Finally we examine potential applications of boson sampling in various fields, including simulation of molecular vibronic spectra in quantum chemistry, and solution of graph-based problems in optimization. These applications demonstrate the wide-ranging impact that boson sampling could have on industries that rely on complex computational models, making it a promising quantum technology for near-term applications.
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[Editor's Pick] Current Optics and Photonics Vol. 8 no. 6 (2024 December)_2nd
Binary-optimization-based Multilayers and Their Practical Applications
Geon-Tae Park, Rira Kang, Byunghong Lee, and Sun-Kyung Kim*
Current Optics and Photonics Vol. 8 No. 6 (2024 December), pp. 545-561
DOI: https://doi.org/10.3807/COPP.2024.8.6.545
Fig. 1 Workflow of binary-optimization-based multilayer design and its applications. (a) Schematic of the iterative optimization cycle, composed of four primary steps [53]. (b) (i) Schematic of antireflective coatings (ARC) applied to a lens, designed to minimize reflectance at the target wavelength λ0 over a wide range of incident angles θ. (ii) Illustration of transparent radiative coolers (TRCs) for energy-saving windows, engineered to reflect ultraviolet and near-infrared light while transmitting visible light, and maintaining high emissivity within the atmospheric window. The red line represents the target transmittance spectrum, and the blue line represents the target emissivity spectrum for an ideal transparent radiative cooler. (iii) Schematic of bandpass filters for thermophotovoltaics (TPVs), designed to enhance the efficiency of the photovoltaic (PV) cell by selective emission. The red dashed line represents the spectral irradiance of a blackbody IBB, and the blue solid line represents the external quantum efficiency (EQE) multiplied by the intensity of blackbody radiation (IBB). The green solid line shows the target spectrum of a selective emitter with unit emissivity.
Keywords: Binary optimization, Machine learning, Multilayer, Optical coating, Optical design
OCIS codes: (200.0200) Optics in computing; (220.0220) Optical design and fabrication; (310.0310) Thin films; (310.1210) Antireflection coatings; (310.6845) Thin film devices and applications
Abstract
Multilayers composed of two or more materials enable the regulation of transmission, reflection, and absorption spectra across one or multiple bands. While analytic formulas based on well-established interference conditions, such as those employed in single-, double-, and triple-layer antireflective coatings and distributed Bragg reflectors, have provided suitable solutions for traditional optical coatings, they are limited in achieving the intricate spectral characteristics required by multifunctional optical coatings. To overcome this limitation, a variety of machine learning-based design algorithms have been rigorously studied. Among these, binary optimization has proven particularly effective for designing multilayer optical coatings. This approach transforms a given multilayer into a binary vector with multiple bits, where each bit represents one of the constituent materials, and quickly identifies an optimal figureof-merit by analyzing the interactions among the elements of the binary vector. In this review article, we elucidate the principles of binary optimization and explore its applications in the design of multilayers for antireflective coatings for high-numerical-aperture lenses, transparent radiative coolers for energysaving windows, and bandpass filters for thermophotovoltaics. Furthermore, we address the limitations, challenges, and perspectives of machine learning-based optical design to guide directions for future research in this field.
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[Editor's Pick] Current Optics and Photonics Vol. 8 no. 6 (2024 December)_1st
A Tutorial on Inverse Design Methods for Metasurfaces
Jin-Young Jeong† , Sabiha Latif† , and Sunae So*
Current Optics and Photonics Vol. 8 No. 6 (2024 December), pp. 531-544
DOI: https://doi.org/10.3807/COPP.2024.8.6.531
Fig. 1 Schematic illustration of an overview of inverse design metasurfaces using machine learning and optimization methods.
Keywords: Inverse design, Machine learning, Metasurface, Optimization algorithm
OCIS codes: (150.1135) Algorithms; (240.0240) Optics at surfaces
Abstract
This paper provides a tutorial on inverse design approaches for metasurfaces with a systematic analysis of the fundamental methodologies and underlying principles for achieving targeted optical properties. Traditionally, metasurfaces have been designed with extensive trial-and-error methods using analytical modeling and numerical simulations. However, as metasurface complexity grows, these conventional techniques become increasingly inefficient in exploring the vast design space. Recently, machine learning and optimization algorithms have emerged as powerful tools for overcoming these challenges and enabling more efficient and accurate inverse design. We begin by introducing the fundamentals of optical simulations used for forward modeling of metasurfaces and their relevance to inverse design. Next, we explore recent advancements in applying machine learning techniques such as neural networks, Markov decision processes, and Monte Carlo simulations, as well as optimization algorithms, including automatic differentiation, the adjoint method, genetic algorithms, and particle swarm optimizations, and show their potential to revolutionize the metasurface design process. Finally, we conclude with a summary of key findings and insights from this review.
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[하이라이트 논문] 한국광학회지 Vol. 35 No.6 (2024 December)
Recent Trends in Bioinspired Camera Systems for Intelligent Robotics
지능형 로봇을 위한 생체모사형 카메라 연구 최신 지견
장진영1ㆍ장세희1ㆍ송영민1,2,3†
한국광학회지 Vol. 35 No.6 (2024 December) pp. 265-375
DOI: https://doi.org/10.3807/KJOP.2024.35.6.265
Fig. 1 (a) Photograph of the tunable hemispherical electronic eye camera system. (b) Photographs of the photodiode array imaged through a lens at different magnifications (left: smaller radius of curvature, right: larger radius of curvature). (c) Image demonstration of a test pattern (left: flat detector, right: detector shape matched to the Petzval surface). (a)–(c) are reprinted from I. Jung et al. Proc. Natl. Acad. Sci. 2011; 108; 1788-1793. Copyright © 2011, National Academy of Sciences [2] . (d) Optical layout showing a monocentric imager designed with a single ball lens. (e) Photographs of the five-gore structure before mounting and curved device positioned in a hemispherical fixture. (d) and (e) are reprinted from T. Wu et al. Microsyst. Nanoeng. 2016; 2; 16019. Copyright © 2016, T. Wu et al. [3] . (f) Photograph of the phototransistor array on a planar substrate. The inset shows an exploded schematic view of a phototransistor structure. (f) is reprinted from C. Choi et al. Nat. Commun. 2017; 8; 1664. Copyright © 2017, C. Choi et al. [6] . (g) Curvature forming method using two axisymmetric models of a spherical wrapping process. (h) Photograph of a curved complementary metal oxide semiconductor (CMOS) image sensor. (g) and (h) are reprinted with permission from Guenter et al. Opt. Express 2017; 25; 13010-13023. Copyright © 2017, Optical Society of America [8].
Keywords: 생체모사형 카메라, 이미지 센서, 비전 시스템
OCIS codes: (040.1490) Cameras; (110.0110) Imaging systems; (220.0220) Optical design and fabrication
초록
지능형 로봇 시대가 도래함에 따라 이미지 센서 또는 카메라 모듈에도 각 수요처에 따른 제품군의 다양화 필요성이 대두되고 있다. 이와 동시에 초소형/저전력 구동부터 하드웨어 레벨 물체 인식까지, 기존 카메라에서 구현하기 어려운 성능에 대한 수요도 늘고 있다. 한편 인간의 눈을 비롯한 자연계 동물의 눈 구조 및 기능의 우수함과 다양성은 미래 비전 시스템 개발에 큰 영감을 준다. 특히 동물의 서식지 및 생활 환경에 적응하기 위해 생태학적으로 진화한 눈에는 기존의 카메라에서 볼 수 없던 기능이 다수 존재하기 때문에, 최근 이를 모방하기 위한 연구가 활발히 이루어지고 있다. 이러한 생체모사형 카메라의 분야는 크게 렌즈 광학계, 이미지 센서, 나노포토닉 구조, 뉴런/시냅스 모사로 나눌 수 있으며, 최근에는 이를 모두 통합하여 하나의 완성된 비전 시스템을 만들기 위한 시도가 이루어지고 있다. 본 리뷰에서는 세부기술별로 나누어 연구 동향을 살피기보다는, 기술의 발전 방향에 따른 생체모사형 카메라 연구의 흐름을 추적하고자 한다.
Abstract
With the advent of the intelligent robotics era, there is an increasing demand for a variety of image sensors and camera modules to meet the needs of various applications. At the same time, demand is growing for performance such as ultra-compact size, low-power operation, and hardware-level object recognition that is difficult to achieve with existing cameras. The superior structures and functionalities of natural eyes, including those of humans and other animals, provide significant inspiration for the development of next-generation artificial vision systems. In particular, the unique characteristics of animal eyes, which have evolved ecologically to adapt to specific habitats and environments, exhibit functionalities beyond those found in conventional cameras. Consequently, research aiming to mimic these natural optical systems has become very active. Bioinspired cameras can generally be categorized into lens optics, image sensors, nanophotonic structures, and neuron/synapse mimics. Recently, there have been attempts to integrate all these components into a complete vision system. This review aims to trace trends in bioinspired cameras, focusing not on the technical aspects of individual components but on overall directions in technological advancement.
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[하이라이트 논문] 한국광학회지 Vol. 35 No.5 (2024 Ocotber)
Soliton Mode-locking and Numerical Analysis of Yb3+-doped Potassium Double Tungstate Lasers in Compact Laser Cavity Geometries
Yb3+ 도핑된 칼륨 이중 텅스테이트 결정을 이용한 소형 공진기에서의 솔리톤 모드 잠금 레이저 구현 및 수치 해석
김덕우 ㆍ고광훈ㆍ이상민†
한국광학회지 Vol. 35 No.5 (2024 October) pp. 241-249
DOI: https://doi.org/10.3807/KJOP.2024.35.5.241
Fig. 1 Schematic of experimental setup. LD, polarization maintaining fiber-coupled laser diode; COL, fiber collimator (NA = 0.50);
HWP, half-wave plate; Lens, pump focusing lens with a focal length of 50 mm; M 1,2 , concave mirrors with a radius of curvature of 50 mm; OC, output coupler; CM, GTI chirped mirror; C, laser crystal.
Keywords: 펨토초 레이저, 모드 잠금, 이터븀
OCIS codes: (140.3580) Lasers, solid-state; (140.3615) Lasers, ytterbium; (140.4050) Mode-locked lasers; (140.7090) Ultrafast lasers; (190.5530) Pulse propagation and temporal solitons
초록
본 연구에서는 Yb3+ 이온이 도핑된 세 종류의 이중 텅스텐 결정, Yb:KGdW, Yb:KYW 및 Yb:KLuW을 사용하여 1039 nm의 중심파장 영역에서 반복율이 405 MHz인 연속파 모드 잠금된 소형 고체 레이저를 구현하였다. 모드 잠금을 위한 광스위칭 소자로 반도체 포화 흡수체 거울을 사용하였고, 모드 잠금 상태들은 세 결정 모두에서 수 시간 이상 Q-스위칭 불안정성 없이 안정적으로 동작하였다. 특히 Yb:KGdW 결정을 이용한 레이저는 최고 출력 125 mW에서 108 fs의 펄스폭을 갖는 펄스를 방출하였다. 또한 표준 분할 단계 푸리에 방법을 이용하여 공진기의 군지연 분산 및 자체 위상 변조를 고려한 Haus Master 방정식을 수치 해석으로 풀고, 그 결과를 실험결과와 비교 및 분석하였다.
Abstract
In this study, we demonstrate compact mode-locked laser operations using three different kinds of Yb3+-doped potassium double tungstate laser crystals, Yb:KGdW, Yb:KYW and Yb:KLuW, operating near 1040 nm at a repetition rate of 405 MHz. We utilized a semiconductor saturable absorber mirror (SESAM) as a mode locker, successfully maintaining mode-locked states for several hours without any Q-switching instabilities for all types of laser crystals. Notably, the Yb:KGdW mode-locked laser produces the shortest pulse with a duration of 108 fs, delivering 125 mW of output power. Additionally, we conducted a numerical analysis by solving the Haus Master equation, which incorporates the effect of group delay dispersion and self-phase modulation, using the standard split-step Fourier method.
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[Editor's Pick] Current Optics and Photonics Vol. 8 no. 5 (2024 October)
Cell Death Inhibition Effect of Antioxidant Activity by 630 and 850 nm LEDs in RAW264.7 Cells
Hee Eun Kim, Eun Young Kim>, Jin Chul Ahn*, and Sang Joon Mo**
Current Optics and Photonics Vol. 8 No. 5 (2024 October), pp. 441-455
DOI: https://doi.org/10.3807/COPP.2024.8.5.441
Fig. 1 Photographs showing the lighting conditions during exposure of RAW264.7 cells to red (left) and near-infrared (right) LED lights.
LED devices for a cell culture plate with an output irradiance of 10 mW/cm2 light at a distance of 5 cm. To cool the LED board, a cooling fan is installed to control temperature rise.
Keywords: Antioxidant activity, Cell death, Light-emitting diode, RAW264.7 cell
OCIS codes: (000.1430) Biology and medicine; (170.0170) Medical optics and biotechnology; (170.1420) Biology; (170.1610) Clinical applications
Abstract
This study objective was to evaluate the effects and mechanisms of low-level laser therapy in H2O2-induced cell death in mouse macrophage RAW264.7 cell. After irradiation with 630 and 850 nm wavelength diode lasers with an intensity of 10 mW/cm2 in RAW264.7 cells treated with 0.7 Mm H2O2, the effects and mechanisms of the two wavelengths on cell death inhibition were evaluated using MTT assay, ROS staining, TUNEL assay, flow cytometry analysis, and Western blot analysis. As a result, 630 or 850 nm light-emitting diodes (LED) were irradiated for 10 or 40 minutes to increase cell viability with H2O2 by about 1.7- or 1.6-fold, respectively. In addition, irradiation with two LEDs showed significant ROS scavenging effects, and TUNEL-positive cells were significantly reduced by 45.7% (630 nm) and 37.8% (850 nm) compared to cells treated with H2O2 alone. The Bax/Bcl-2 ratio of cells irradiated with both LEDs was significantly lower than that of cells treated with H2O2 only, and the expression of procaspase-3 and cleaved PARP was also significantly expressed in the direction of suppressing cell death. In conclusion, ROS scavenging activity by both LEDs irradiation leads to the expression of cell death pathway proteins in the direction of inhibiting cell death.
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[하이라이트 논문] 한국광학회지 Vol. 35 No.4 (2024 August)
Hyperlens and Metalens-based Biomedical Imaging
하이퍼렌즈 및 메타렌즈 기반 바이오메디컬 이미징
박혜미1,2 *ㆍ조용재1 *ㆍ김인기1,2†
한국광학회지 Vol. 35 No.4 (2024 August) pp. 135-142
DOI: https://doi.org/10.3807/KJOP.2024.35.4.135
Fig. 1 Examples of metamaterials operating at various wavelengths. The working mechanism and operation wavelength vary depending on the materials and structures. (a) V-shaped antenna metamaterial fabricated on a silicon wafer. Reprinted with permission from N. Yu et al. Science 2011; 334; 333-337. Copyright © 2011, The American Association for the Advancement of Science [7] . (b), (c) Scanning electron microscope images of square-shaped crystalline silicon metamaterials. Reprinted with permission from H. Liang et al. Nano Lett. 2018; 18; 4460-4466. Copyright © 2018, American Chemical Society [8] . (d) Chiral metamaterial fabricated by electron beam lithography. Scale bar: 500 nm. Reprinted with permission from [9] Copyright © 2007, Optical Society of America. (e) Fishnet structure metamaterial fabricated by nanoimprint lithography. Reprinted with permission from W. Wu et al. Appl. Phys. A 2007; 87; 143-150. Copyright © 2007, Springer-Verlag [10] . (f) Scanning electron microscope images of hyperbolic metamaterials composed of silver/germanium multilayers, shown with two, three, and four pairs of layers, respectively. Reprinted with permission from X. Yang et al. Nat. Photonics 2012; 6; 450-454. Copyright © 2012, Springer Nature Limited [11] .
Keywords: 바이오 메디컬 이미징, 하이퍼렌즈, 메타렌즈, 메타물질
OCIS codes: (160.3918) Metamaterials; (170.3880) Medical and biological imaging; (220.0220) Optical design and fabrication
초록
바이오 메디컬 이미징 기술은 생물학적 연구 및 의료 기술에 사용되는 이미징 기법으로서 생물학적 과정, 구조 및 상태를 탐구하는 데 필수이 며, 질병의 조기 진단과 치료법 개발에도 중요한 역할을 하고 있다. 그중에서도 특히 빛을 이용한 광학 이미징 기술은 생물학 연구에서 가장 많이 활용되고 활발하게 연구되고 있다. 광학 이미징 기술의 발전에 가장 큰 걸림돌이 되고 있는 것은 해상도 및 빛의 투과 깊이 한계 등의 문제 인데, 최근에는 메타물질을 이용하여 이를 해결하고자 하는 연구가 활발해지고 있는 추세이다. 메타물질은 나노구조체의 규칙적인 배열을 통해 빛의 성질을 자유롭게 조절하는 물질로서, 이미징 분야에서는 이미 혁신적인 도구로 자리잡고 있다. 이 글에서는 메타물질을 활용한 광학 이미징 기술의 작동 원리와 주요 응용 사례에 대해 자세히 소개하고자 한다
Abstract
Biomedical imaging technologies refer to imaging techniques used in biological research and medical technology that are essential for exploring biological processes, structures, and conditions. They also play a crucial role in the early diagnosis of diseases and the development of treatments. Optical imaging technologies, in particular, are the most widely used and actively researched in biological studies. The major obstacles to technological advancement are the limitations in resolution and light penetration depth. Recently, many technologies have been studied to overcome these limitations using metamaterials. These are materials that can freely manipulate the properties of light through the regular arrangement of nanostructures and have established themselves as innovative tools in the imaging field. This article aims to provide a detailed introduction to the working principles and key applications of these technologies.
