게시판
최근논문
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[하이라이트 논문] 한국광학회지 Vol. 34 No.2 (2023 April)
적색 및 적외선 빛을 이용한 Photobiomodulation: 각막상피세포에 대한 효과와 상처 치유에 관한 연구
Photobiomodulation Mediated by Red and Infrared Light: A Study of Its Effectiveness on Corneal Epithelial Cells and Wound Healing
안선희1ㆍ안재성1ㆍ이병일2†
한국광학회지 Vol. 34 No.2 (2023 April) pp. 45-52
DOI: https://doi.org/10.3807/KJOP.2023.34.2.045
Fig. 1 Representative picture of the experimental setup and emission spectra of light-emitting diodes (LEDs). (a) LEDs were irradiated to the 24-well plate from the top and a single-well-shaped mask was fixed on the top surface of the well plate to prevent LED light from being irradiated to adjacent wells. The power of LED light transmitted through the mask was measured with a photodiode sensor to derive the amount of light energy irradiated to the sample. (b) Normalized spectra of LED light sources.
Keywords: 각막상피세포, 저출력광치료, 광생물조절, 상처치료
OCIS codes: (170.1530) Cell analysis; (350.5130) Photochemistry
초록
본 연구에서는 다양한 파장의 저출력 light-emitting diode (LED)를 이용한 photobiomodulation (PBM)이 각막 상처 치유에 미치는 영향을 분석하였다. 각막상피세포에 623 nm에서 940 nm 범위의 파장의 LED를 조사한 결과, 유의미한 세포독성 영향을 미치지 않는 것을 확인하였다. PBM의 세포이동 촉진 효과를 세포 이동능 평가 시험을 통해 분석한 결과 623 nm 파장의 광조사에 의한 PBM이 세포이동을 크게 증가시키고 상처 치유를 촉진하는 것으로 나타났다. 또한, 세포이동 및 상처 치유와 관련된 유전자의 발현을 분석한 결과, 623 nm 파장의 광조사에 의한 PBM이 세포 증식과 세포 외 기질 분해를 촉진하는 것으로 알려진 FGF-1과 MMP2 유전자의 발현을 상향 조절한다는 사실을 발견했다. 이러한 연구 결과는 특정 파장, 특히 623 nm 파장의 저출력 빛을 이용한 PBM이 각막 손상 치료에 활용될 수 있는 가능성을 시사한다.
Abstract
In this study, we have investigated the effect of photobiomodulation (PBM) on corneal wound healing, using a low-power light-emitting diode (LED) at different wavelengths. We found that LEDs with wavelengths ranging from 623 to 940 nm had no significant cytotoxic effects on corneal epithelial cells. The effect of PBM on promoting cell migration was analyzed by scratch assay, and it was found that PBM at 623 nm significantly increased cell migration and promoted wound healing. Furthermore, the expression of genes related to cell migration and wound healing was analyzed, and it was found that PBM at 623 nm upregulated the expression of the genes FGF-1 and MMP2, which are known to promote cell proliferation and extracellular matrix degradation. These findings suggest that PBM with low-powered light at specific wavelengths, particularly 623 nm, could be utilized to treat corneal injury.
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[Editor's Pick] Current Optics and Photonics Vol. 7 no. 2 (2023 April)
A Wide-field-of-view Table-ornament Display Using Electronic Holography
Daerak Heo, Hosung Jeon, Sungjin Lim, and Joonku Hahn*
Current Optics and Photonics Vol. 7 No. 2 (2023 April) pp. 182-190
DOI: https://doi.org/10.3807/COPP.2023.7.2.183
Fig. 1 Schematic of the 3f parabolic imaging optics.
Keywords: Electronic holography, High-speed scanner, Tabletop displays, Three-dimensional display, Viewing zone
OCIS codes: (090.2870) Holographic display; (100.6890) Three-dimensional image processing; (120.5800) Scanners; (220.4830) Systems design; (330.1400) Vision-binocular and stereopsis
Abstract
Three-dimensional (3D) displays provide a significant advantage over traditional 2D displays by offering realistic images, and table-style displays in particular are ideal for generating 3D images that appear to float above a table. These systems are based on multiview displays, and are typically operated using temporal or spatial multiplexing methods to expand the viewing zone (VZ). The VZ is an expanded space that results from merging the sub-viewing zones (SVZs) from which an individual view is made. To increase the viewing angle, many SVZs are usually required. In this paper, we propose a tableornament electronic holographic display that utilizes 3f parabolic mirrors. In holography, the VZ is not simply expanded but synthesized from SVZs to implement continuous motion parallax. Our proposed system is small enough to be applied as a table ornament, in contrast to traditional tabletop displays that are large and not easily portable. By combining multiview and holographic technologies, our system achieves continuous motion parallax. Specifically, our system projects 340 views using a time-multiplexing method over a range of 240 degrees.
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[하이라이트 논문] 한국광학회지 Vol. 34 No.1 (2023 February)
피조 간섭계를 이용한 단일 조각거울 광축방향 변위 오차 측정
Measurement of the Axial Displacement Error of a Segmented Mirror Using a Fizeau Interferometer
장하림1,2ㆍ최재혁2ㆍ송재봉2ㆍ김학용1,2 †
한국광학회지 Vol. 34 No.1 (2023 February) pp. 22-30
DOI: https://doi.org/10.3807/KJOP.2023.34.1.022
Fig. 1 Relationship between axial displacement error and defocus. RoC, radius of curvature.
Keywords: 인공위성, 조각거울, 광축방향 변위 오차, 초점오차
OCIS codes: (120.3180) Interferometry; (120.3940) Metrology; (120.6085) Space instrumentation; (120.6650) Surface measurements, figure; (230.4040) Mirrors
초록
조각거울은 우주용 관측위성의 주반사경을 크게 제작하기 위한 방법 중 하나로서, 여러 개의 작은 거울들을 이어 하나의 큰 거울로 이용하는 방법이다. 여러 개의 거울들을 하나의 거울로 정렬하기 위해서는 인접한 거울들 간에 기울기 오차(tilt)와 광축방향 정렬오차(piston)가 없어야 한다. 기울기 오차와 광축방향 정렬오차를 해결해야 여러 개의 거울이 한 방향으로 빛을 모으고, 이를 통해 뚜렷한 이미지를 얻을 수 있기 때문에 조각거울의 정렬오차를 나노미터 수준으로 측정할 수 있는 파면 센서가 필요하다. 기울기 오차는 조각거울을 통해 얻은 이미지를 통해 어떤 거울의 기울기가 틀어졌는지 쉽게 확인할 수 있는 반면, 광축방향 정렬오차는 이미지의 질은 떨어뜨리지만 드러나는 뚜렷한 특징이 없기 때문에 같은 방법으로 감지하기 어려워 세밀한 측정이 매우 중요하다. 이를 위해 본 논문에서는 지상용 초기 정렬시 많은 이점을 갖는 광학계 평가용 간섭계 중 하나인 피조 간섭계를 이용한다. 피조 간섭계를 사용한 복수 조각거울의 광축방향 정렬오차 측정을 위한 기초 연구로서 단일 조각거 울의 광축방향 변위 오차를 측정하고, 측정불확도를 계산해서 피조 간섭계의 광축방향 변위 오차 측정 한계를 규명한다. 또한 수식을 통해 조각 거울 광축방향 변위 오차와 간섭계로 측정한 표면 초점오차(defocus)의 관계를 계산했고, 도출한 수식의 타당성을 실험으로 검증했다.
Abstract
A segmented mirror is one of the ways to make the primary mirror of a spaceborne satellite larger, and several small mirrors are used as a large monolithic mirror. To align multiple segmented mirrors as one large mirror, there must be no discontinuity in x, y-axis (tilt) and axial alignment error (piston) between adjacent mirrors. When the tilt and piston are removed, we can collect the light in one direction and get an expected clear image. Therefore, we need a precise wavefront sensor that can measure the alignment error of the segmented mirrors in nm scale. The tilt error can be easily detected by the point spread image of the segmented mirrors, while the piston error is hard to detect because of the absence in apparent features, but makes a downgraded image. In this paper we used an optical testing interferometer such as a Fizeau interferometer, which has various advantages when aligning the segmented mirror on the ground, and focused on measuring the axial displacement error of a segmented mirror as the basic research of measuring the piston errors between adjacent mirrors. First, we calculated the relationship between the axial displacement error of the segmented mirror and surface defocus error of the interferometer and verified the calculated formula through experiments. Using the experimental results, we analyzed the measurement uncertainty and obtained the limitation of the Fizeau interferometer in detecting axial displacement errors.
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[Editor's Pick] Current Optics and Photonics Vol. 7 no. 1 (2023 February)
Partial Spectrum Detection and Super-Gaussian Window Function for Ultrahigh-resolution Spectral-domain Optical Coherence Tomography with a Linear-k Spectrometere
Hyun-Ji Lee1,2 and Sang-Won Lee1,2 *
Current Optics and Photonics Vol. 7 No. 1 (2023 February) pp. 73-82
DOI: https://doi.org/10.3807/COPP.2023.7.1.73
Fig. 1 Schematic of the SD-OCT based on a linear k-domain spectrometer. (a) The sample arm to measure the system performance and obtain the skin tissue’s image. (b) The sample arm to get the image of the retina. SD-OCT, spectral domain optical coherence tomography; PC, polarization controller; CL, collimation lens; OL, objective lens; DCB, dispersion compensation block; RM, reference mirror; RC, reflective collimator; G, grating; DP, dispersive prism; PM, prism mirror; L1 to L4, lenses.
Keywords: Spectral domain, Super-Gaussian window, Ultrahigh resolution optical coherence tomography
OCIS codes: (110.4500) Optical coherence tomography; (170.3880) Medical and biological imaging;(170.4500) Optical coherence tomography
Abstract
In this study, we demonstrate ultrahigh-resolution spectral-domain optical coherence tomography with a 200-kHz line rate using a superluminescent diode with a −3-dB bandwidth of 100 nm at 849 nm. To increase the line rate, a subset of the total number of camera pixels is used. In addition, a partialspectrum detection method is used to obtain OCT images within an imaging depth of 2.1 mm while maintaining ultrahigh axial resolution. The partially detected spectrum has a flat-topped intensity profile, and side lobes occur after fast Fourier transformation. Consequently, we propose and apply the super-Gaussian window function as a new window function, to reduce the side lobes and obtain a result that is close to that of the axial-resolution condition with no window function applied. Upon application of the super-Gaussian window function, the result is close to the ultrahigh axial resolution of 4.2 μm in air, corresponding to 3.1 μm in tissue (n = 1.35).
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[하이라이트 논문] 한국광학회지 Vol. 33 No.6 (2022 December)
기하 위상 렌즈 기반의 색공초점 센서를 이용한 투명 물질 두께 측정 연구
Using a Chromatic Confocal Sensor Based on a Geometric Phase Lens
송민관ㆍ박효미ㆍ주기남†
한국광학회지 Vol. 33 No.6 (2022 December) pp. 317-323
DOI: https://doi.org/10.3807/KJOP.2022.33.6.317
Fig. 1 Optical configuration of the chromatic confocal sensor using a geometric phase lens. OC, optical circulator; CL, collimating lens; GPL, geometric phase lens; QWP, quarter-wave plate; S, specimen; LHP, left-handed circular polarization; RHP, right-handed circular polarization.
Keywords: 색공초점 센서, 기하 위상 렌즈, 두께 측정
OCIS codes: (120.3930) Metrological instrumentation; (180.1790) Confocal microscopy
초록
본 논문에서는 투명한 물질의 두께를 측정하기 위한 방법으로 기하 위상 렌즈 기반의 색공초점 센서를 개발하고, 성능 개선을 위한 보정 방법을 제시한다. 일반적인 색공초점 센서의 복잡한 설계로 인한 한계를 극복하기 위해, 기하 위상 렌즈를 이용하여 전체 시스템의 크기를 줄이고, 시스템 오차를 보상하기 위한 파장 첨두 위치 추출 방법과 계통 오차 제거 방법을 설명한다. 색공초점 센서를 이용하여 투명한 물질의 두께를 측정하기 위한 이론을 설명하고, 이를 사파이어 및 BK7 물질의 두께를 측정함으로써 실험적으로 검증한다. 색공초점 센서를 이용한 두께 측정 방법은 기존의 간섭계 및 공초점 센서의 방법들에 비해 측정 속도가 빠르고, 분산 등에 의한 두께 측정 영역 제한이 없기 때문에 많은 응용이 가능하다.
Abstract
In this investigation, we describe a chromatic confocal sensor based on a geometric phase lens for measuring the thicknesses of transparent plates. In order to design a compact sensor, a geometric phase lens, which has diffractive and polarizing characteristics, is used as a device to generate chromatic aberration, and a fiber optic module is adopted. The systematic error of the sensor is reduced with wavelength peak detection by Gaussian curve fitting and the common error compensation obtained by the repeatedly consecutive experimental results. An approach to calculate the plate thickness is derived and verified with sapphire and BK7 plates. Because of the simple and compact design of the proposed sensor with rapid measurement capability, it is expected to be widely used in thickness measurements of transparent plates as an alternative to traditional approaches.
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[Editor's Pick] Current Optics and Photonics Vol. 6 no. 6 (2022 December)
Terahertz Nondestructive Time-of-flight Imaging with a Large Depth Range
Hwan Sik Kim1, Jangsun Kim2, and Yeong Hwan Ahn1*
Current Optics and Photonics Vol. 6 No. 6 (2022 December) pp. 619-626
DOI: https://doi.org/10.3807/COPP.2022.6.6.619
Fig. 1 Experimental setup: A schematic illustration of the THz- time of flight (TOF) imaging setup based on the asynchronous optical sampling (ASOPS) method.
Keywords: Terahertz spectroscopy and imaging, Three-dimensional imaging
OCIS codes: (110.6795) Terahertz imaging; (110.6880) Three-dimensional image acquisition; (300.6495) Spectroscopy, terahertz
Abstract
In this study, we develop a three-dimensional (3D) terahertz time-of-flight (THz-TOF) imaging technique with a large depth range, based on asynchronous optical sampling (ASOPS) methods. THz-TOF imaging with the ASOPS technique enables rapid scanning with a time-delay span of 10 ns. This means that a depth range of 1.5 m is possible in principle, whereas in practice it is limited by the focus depth determined by the optical geometry, such as the focal length of the scan lens. We characterize the spatial resolution of objects at different vertical positions with a focal length of 5 cm. The lateral resolution varies from 0.8–1.8 mm within the vertical range of 50 mm. We obtain THz-TOF images for samples with multiple reflection layers; the horizontal and vertical locations of the objects are successfully determined from the 2D cross-sectional images, or from reconstructed 3D images. For instance, we can identify metallic objects embedded in insulating enclosures having a vertical depth range greater than 30 mm. For feasible practical use, we employ the proposed technique to locate a metallic object within a thick chocolate bar, which is not accessible via conventional transmission geometry.
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[Editor's Pick] Current Optics and Photonics Vol. 6 no. 5 (2022 October)
Cerebral Oxygenation Monitoring during a Variation of Isoflurane Concentration in a Minimally Invasive Rat Model
Dong-Hyuk Choi1, Sungchul Kim1, Teo Jeon Shin2, Seonghyun Kim1, and Jae Gwan Kim1 *
Current Optics and Photonics Vol. 6 No. 5 (2022 October) pp. 489-496
DOI: https://doi.org/10.3807/COPP.2022.6.5.489
Fig. 1 Schematic comparison of invasive and minimally invasive models.
Keywords: Cerebral blood volume, Depth of anesthesia, Isoflurane, Monte Carlo simulation, Near-infrared spectroscopy
OCIS codes: (170.1610) Clinical application; (170.2655) Functional monitoring and imaging; (170.4580) Optical diagnostics for medicine; (170.6510) Spectroscopy, tissue diag nostics
Abstract
Our previous study on monitoring cerebral oxygenation with a variation of isoflurane concentration in a rat model showed that near-infrared spectroscopy (NIRS) signals have potential as a new depth of anesthesia (DOA) index. However, that study obtained results from the brain in a completely invasive way, which is inappropriate for clinical application. Therefore, in this follow-up study, it was investigated whether the NIRS signals measured in a minimally invasive model including the skull and cerebrospinal fluid layer (CSFL) are similar to the previous study used as a gold standard. The experimental method was the same as the previous study, and only the subject model was different. We continuously collected NIRS signals before, during, and after isoflurane anesthesia. The isoflurane concentration started at 2.5% (v/v) and decreased to 1.0% by 0.5% every 5 min. The results showed a positive linear correlation between isoflurane concentration and ratio of reflectance intensity (RRI) increase, which is based on NIRS signals. This indicates that the quality of NIRS signals passed through the skull and CSFL in the minimally invasive model is as good as the signal obtained directly from the brain. Therefore, we believe that the results of this study can be easily applied to clinics as a potential indicator to monitor DOA.
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[Editor's Pick] Current Optics and Photonics Vol. 6 no. 4 (2022 August)
A New Instrument for Measuring the Optical Properties of Wide-field-of-view Virtual-reality Devices
Hee Kyung Ahn1, Hyun Kyoon Lim2, and Pilseong Kang1 *
Current Optics and Photonics Vol. 6 No. 4 (2022 August) pp. 392-399
DOI: https://doi.org/10.3807/COPP.2022.6.4.392
Fig. 1 The structure of a typical light-measuring devices (LMD) for virtual-reality/augmented-reality (VR/AR) devices.
Keywords: Augmented Reality, Spectroradiometer, Virtual Reality
OCIS codes: (120.2040) Displays; (120.5240) Photometry
Abstract
ght-measuring devices (LMDs) are frequently used to measure luminance and color coordinates of displays. However, it is very difficult to use a conventional LMD for measuring the optical properties of virtual-reality (VR) devices with a wide field of view (FOV), because of their confined spaces where the entrance pupil of a LMD is located. In this paper, a new LMD that can measure the optical properties of wide-FOV VR devices, without physical conflict with the goggles of the VR device, is proposed. The LMD is designed to fully satisfy the requirements of IEC 63145-20-10, and a pivot-point correction method for the LMD is applied to improve its accuracy. To show the feasibility of the developed LMD and the correction method, seven VR devices with wide FOV are measured with it. From the results, all of them are successfully measured without any physical conflict, and a comparison to their nominal values shows that the FOVs have been properly measured.
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