• 한국자기학회:학술대회 개요집
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• 한국자기학회 2014년도 자성 및 자성재료 국제학술대회
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• pp.103-103
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• 2014

• ETRI Journal
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• 제23권3호
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• pp.106-110
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• 2001

Subpicosecond all-optical switching method based on the simultaneous two-photon coherence exchange is proposed and numerically demonstrated. The optical switching mechanism is based on the optical field induced dark resonance swapping via nondegenerate four-wave mixing processes. For potential applications of ultrafast all-optical switching in fiber-optic communications, 10-THz channel number independent quantum router is discussed.

• 한국광학회지
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• 제31권1호
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• pp.31-36
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• 2020

본 논문에서는 온도 변화에 따라 절연체-금속 상전이 특성을 보이는 이산화바나듐(VO₂)를 식각한 도선과 금속 도선을 조합한 밴드-전환형 테라헤르츠 메타물질을 제시하였다. 갭을 가지는 금속 사각 구조 가운데 식각된 VO₂ 도선을 위치시킨 구조와 VO₂ 상전이 특성을 이용하여 제안된 메타물질의 가변성을 확보하였다. 설계한 VO₂ 기반 메타물질은 VO₂의 절연체-금속 상전이 특성에 따라 공진 주파수가 1.4 THz에서 0.7 THz으로 전환되었다. 이때, 제안한 메타물질의 절대 투과율은 0.7 THz와 1.4 THz에서 각각 78.5%와 65.8%로 높은 변화율을 가지고, 전환이 가능한 두 공진 주파수 중간 대역에서 40%와 60% 사이의 안정적인 투과율을 보이면서 균일하게 90도의 높은 차등 위상 변위 특성을 보였다.

• Current Optics and Photonics
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• 제6권3호
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• pp.252-259
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• 2022

In this paper, a dual-function dynamically tunable metamaterial absorber is proposed. At frequency points of 1.545 THz and 3.21 THz, two resonance peaks with absorption amplitude of 93.8% (peak I) and 99.4% (peak II) can be achieved. By regulating the conductivity of photosensitive silicon with a pump laser, the resonance frequency of peak I switches to 1.525 THz, and that of peak II switches to 2.79 THz. By adjusting the incident polarization angle by rotating the device, absorption amplitude tuning is obtained. By introducing two degrees of regulation freedom, the absorption amplitude modulation and resonant frequency switching are simultaneously realized. More importantly, dynamic and continuous adjustment of the absorption amplitude is obtained at a fixed resonant frequency, and the modulation depth reaches 100% for both peaks. In addition, the sensing property of the proposed MMA was studied while it was used as a refractive index sensor. Compared with other results reported, our device not only has a dual-function tunable characteristic and the highest modulation depth, but also simultaneously possesses fine sensing performance.

• Journal of electromagnetic engineering and science
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• 제10권3호
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• pp.158-165
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• 2010

This study reviewed terahertz technologies of time domain spectroscopy, T-ray imaging, and high rate wireless data transfer. The main topics of the terahertz research area were investigation of materials and package modules for terahertz wave generation and detection, and setup of the terahertz system for time domain spectroscopy(TDS), T-ray imaging and sub-THz wireless communication. In addition to Poly-GaAs film as a photoconductive switching antenna material, a table-top scale for the THz-TDS/imaging system and terahertz continuous wave(CW) generation systems for sub-THz data transfer and narrow band T-ray imaging were designed. Dielectric properties of ferroelectric BSTO($Ba_xSr_{1-x}TiO_3$) films and chalcogenide glass systems were characterized with the THz-TDS system at the THz frequency range. Package modules for terahertz wave transmitter/receiver(Tx/Rx) photoconductive antenna were developed.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권10호
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• pp.5035-5057
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• 2019

Advancements in nanotechnology and novel nano materials in the past decade have provided a set of tools that can be used to design and manufacture integrated nano devices, which are capable of performing sensing, computing, data storing and actuation. In this paper, we have proposed cooperative nano communication using Power Switching Relay (PSR) Wireless Power Transfer (WPT) protocol and Time Switching Relay (TSR) WPT protocol over independent identically distributed (i.i.d.) Rayleigh fading channels in the Terahertz (THz) Gap frequency band to increase the range of transmission. Outage Probability (OP) performances for the proposed cooperative nano communication networks have been evaluated for the following scenarios: A) A single decode-and-forward (DF) relay for PSR protocol and TSR protocol, B) DF multi-relay network with best relay selection (BRS) for PSR protocol and TSR protocol, and C) DF multi-relay network with multiple DF hops with BRS for PSR protocol and TSR protocol. The results have shown that the transmission distance can be improved significantly by employing DF relays with WPT. They have also shown that by increasing the number of hops in a relay the OP performance is only marginally degraded. The analytical results have been verified by Monte-Carlo simulations.

• Carbon letters
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• 제21권
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• pp.8-15
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• 2017

The thermoelectric Seebeck and Peltier effects of a single walled carbon nanotube (SWCNT) quantum dot nanodevice are investigated, taking into consideration a certain value of applied tensile strain and induced ac-field with frequency in the terahertz (THz) range. This device is modeled as a SWCNT quantum dot connected to metallic leads. These two metallic leads operate as a source and a drain. In this three-terminal device, the conducting substance is the gate electrode. Another metallic gate is used to govern the electrostatics and the switching of the carbon nanotube channel. The substances at the carbon nanotube quantum dot/metal contact are controlled by the back gate. Results show that both the Seebeck and Peltier coefficients have random oscillation as a function of gate voltage in the Coulomb blockade regime for all types of SWCNT quantum dots. Also, the values of both the Seebeck and Peltier coefficients are enhanced, mainly due to the induced tensile strain. Results show that the three types of SWCNT quantum dot are good thermoelectric nanodevices for energy harvesting (Seebeck effect) and good coolers for nanoelectronic devices (Peltier effect).