• Journal of electromagnetic engineering and science
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• 제9권2호
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• pp.105-109
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• 2009

The problem of electromagnetic coupling between a slit fed by a flanged parallel-plate waveguide(PPW) and a slit in an infinite nearby conducting screen parallel to the flanged ground conductor is studied as a simplified problem for a near-field scanning microscopy(NSM). The method of moments isused to solve the coupled integral equations for the electric field distributions over the slits. The performance of the proposed apparatus as an NSM is tested by examining the effects of some geometrical parameters on the equivalent slit admittance and coupled powers through the slits.

• Journal of Magnetics
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• 제18권3호
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• pp.317-320
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• 2013

We studied the polarization state in an apertureless scanning near-field microscopy (a-SNOM) operating in reflection mode by using three-dimensional Finite-difference Time-domain (FDTD) method. As a result, the electric field around tip apex in the near-field region enhanced four times stronger than the incident light for ppolarization when the tip-sample separation was 10 nm. We find that the p- and s-polarization state is maintained for the scattered light when the probe is perpendicular to the sample. When the probe is not perpendicular to the sample, the polarization state of scattered light will rotate an angle that equals to the inclination angle of probe with p-polarization illumination. On the other hand, the polarization state will not rotate with s-polarization illumination.

• Journal of Electrical Engineering and Technology
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• 제13권1호
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• pp.406-412
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• 2018

In this paper, we propose a narrow resonant waveguide probe that can improve the measurement sensitivity in near-field scanning microwave microscopy. The probe consists of a metal waveguide incorporating the following two sections: a straight section at the tip of the probe whose cross-section is a double-ridged rectangle, and whose height is much smaller than the waveguide width; and a standard waveguide section. The advantage of the narrow waveguide is the same as that of the quarter-wave transformer section i.e., it achieves impedance-matching between the sample under test (SUT) and the standard waveguide. The design procedure used for the probe is presented in detail and the performance of the designed resonant probe is evaluated theoretically by using an equivalent circuit. The calculated results are compared with those obtained using the finite element method (Ansoft HFSS), and consistency between the results is demonstrated. Furthermore, the performance of the fabricated resonant probe is evaluated experimentally. At X-band frequencies, we have measured the one-dimensional scanning reflection coefficient of the SUT using the probe. The sensitivity of the proposed resonant probe is improved by more than two times as compared to a conventional waveguide cavity type probe.

• 세라미스트
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• 제10권3호
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• pp.55-66
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• 2007

Infrared Scanning Near-field Optical Microscopy (IR-SNOM) is an extremely powerful analytical instrument since it combines IR spectroscopy's high chemical specificity with SNOM's high spatial resolution. In order to do this in the infrared, specialty chalcogenide glass fibers were fabricated and their ends tapered to generate SNOM probes. The fiber tips were installed in a modified near field microscope and both inorganic and biological samples illuminated with the tunable output from a free-electron laser located at Vanderbilt University. Both topographical and IR spectral images were simultaneously recorded with a resolution of ${\sim}50\;nm$ and ${\sim}100\;nm$, respectively. Unique spectroscopic features were identified in all samples, with spectral images exhibiting resolutions of up to ${\lambda}/60$, or at least 30 times better than the diffraction limited lens-based microscopes. We believe that IR-SNOM can provide a very powerful insight into some of the most important bio-medical research topics.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 춘계학술대회 논문집 디스플레이 광소자분야
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• pp.137-141
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• 2004

저항특성이 다른 ITO박막의 구조특성과 표면특성을 XRD와 AFM(atomic force microscopy), SEM(scanning electron microscopy)을 이용하여 관측하였다. 접촉방식인 4단자 법을 사용하여 ITO박막의 표면전기저항을 측정하였다. 관측된 구조 및 표면특성을 바탕으로 비파괴 비접촉방식을 이용한 근접장 마이크로파 현미경을 이용하여 얻은 ITO박막의 표면저항특성과 비교 연구하였다.

• 한국정보통신학회논문지
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• 제13권11호
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• pp.2260-2266
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• 2009

본 논문에서는 플랜지된 평행평판도파관으로 급전된 슬릿과 이에 평행하고 근접하는 도체 스트립과의 전자기적인 결합문제를 단순화된 근접주사현미 경의 관점에서 연구하였다. 슬릿의 등가어드미턴스, 슬릿근처 도파관 내부 및 외부의 무효전력, TEM파 전압반사계수의 크기 및 위상 등의 변화결과로부터 플랜지된 평행평판도파관의 특성을 조사하였다. 제안된 구조의 근접주사현미경으로서의 성능을 다양한 구조적인 파라미터들(도파관 높이, 슬릿의 폭, 스트립의 폭, 슬릿과 스트립 간격, 슬릿 폭과 도파관 높이의 비)이 TEM파 전압반사계수의 크기와 위상에 미치는 영향을 관찰하여 점검하였다. 슬릿으로부터 스트립의 변위에 따른 전압반사계수의 변화결과로부터 도파관의 높이가 작을 때 보다 높은 주사해상도를 얻을 수 있음과 반사계수의 크기 변화에 비해 위상변화가 훨씬 민감함을 확인하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 영호남학술대회 논문집
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• pp.327-330
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• 2000

The scanning Maxwell-stress microscopy (SMM) is a dynamic noncontact electric force microscopy that allows simultaneous access to the electrical properties of molecular system such as surface potential, surface charge, dielectric constant and conductivity along with the topography. The Scanning near-field optical / atomic force microscopy (SNOAM) is a new tool for surface imaging which was introduced as one application of the atomic force microscope (AFM). Operated with non-contact forces between the optical fiber and sample as well as equipped with the piezoscanners, the instrument reports on surface topology without damaging or modifying the surface for measuring of optical characteristic in the films. We report our recent results of its application to nanoscopic study of domain structures and electrical functionality in organic thin films by SMM. Furthermore, we have illustrated the SNOAM image in obtaining the merocyanine dye films as well as the optical image.

• Journal of Electrical Engineering and Technology
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• 제10권5호
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• pp.2120-2125
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• 2015

In this paper, a rectangular waveguide probe with a ridge-loaded straight slot (RLSS) is presented for a near-field scanning microwave microscope (NSMM). The RLSS is located laterally at the end wall of the cavity and is loaded on double ridges in a narrow straight slot to improve the spatial resolution compared with a straight slot. The probe consists of a rectangular cavity with an RLSS and a feed section of a WR-90 rectangular waveguide. When the proposed NSMM is located at distance of 0.1mm in front of a substrate without patches or strips, the simulated full width at half maximum (FWHM) of the probe improve by approximately 31.5 % compared with that of a straight slot without ridges. One dimensional scanning of the E-plane on a sample under test was conducted, and the reflection coefficient of the near-field scanning probe is presented.

• 한국광학회:학술대회논문집
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• 한국광학회 2002년도 하계학술발표회
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• pp.122-123
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• 2002

능동적으로 안정화시킨 반도체 레이저의 빛살되먹임을 이용한 근접장 광학현미경(Near-field Scanning Optical Microscope)을 이용하여 칼코게나이드계 유리인 a-As$_2$S$_3$에서 광조사에 따른 자체집광 현상과 구조변화를 관찰하였다. 여러 비선형 광학현상 중 광 커르 효과(Optical Kerr effect)에 기인하는 자체집광(Self-focusing)은 광범위하게 연구되어 왔다. (중략)

• 한국광학회:학술대회논문집
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• 한국광학회 2001년도 제12회 정기총회 및 01년도 동계학술발표회
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• pp.60-61
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• 2001

We present our experimental results on the recording and retrieving of multiplexed near-field holograms using near-field scanning optical microscopy (NSOM) and a conventional rectangular-parallelepiped or cubic photorefractive crystal. Experimental results show that we can get the angular selectivity comparable with that of the volume hologram and the retrieved spot size was smaller than the Rayleigh's limit. The results also show that the angular selectivity and the retrieved spot size are strongly dependent on the recording distance between the object and the recording medium.