Clare Chisu Byeon

Fabrication of a fused silica based mold for the microlenticular lens array using a femtosecond laser and a CO 2 laser

Many techniques have been suggested and investigated for the microlens array fabrication in three dimensional structures. We present the fabrication of a fused silica based mold for the microlenticular lens array using a femtosecond laser and a CO2 laser. The three dimensional microlenticular array mold is surface-machined on a fused silica plate by a femtosecond laser and polished with a CO2 laser. The CO2 laser treatment process can be customized to obtain a smooth surface. To evaluate the performance of the fabricated glass mold, we replicated a PDMS microlenticular lens arrays from the fabricated glass micro lenticular array mold.

Operation of a wet near-field scanning optical microscope in stable zones by minimizing the resonance change of tuning forks

A resonant shift and a decrease of resonance quality of a tuning fork attached to a conventional fiber optic probe in the vicinity of liquid is monitored systematically while varying the protrusion length and immersion depth of the probe. Stable zones where the resonance modification as a function of immersion depth is minimized are observed. A wet near-field scanning optical microscope (wet-NSOM) is operated for a sample within water by using such a stable zone.

Optical characterization of nanomaterials

1 Department of Energy Science, Center for Integrated Nanostructure Physics, Institute for Basic Science, Sungkyunkwan University, Suwon 440-746, Republic of Korea 2Department of Electrical and Computer Engineering, Old Dominion University, Norfolk, VA 23529, USA 3 School of Mechanical Engineering, Kyungpook National University, Daegu 702-701, Republic of Korea 4Department of Physics, Yeungnam University, Gyeongsan 712-749, Republic of Korea 5 Department of Physics, Jeju National University, Jeju 690-756, Republic of Korea

Development of Single-Channel Thread Sensor for Rotary Bobbin by Optical Sensing

* School of Mechanical Engineering, Kyungpook Nat’l Univ.(Received February 20, 2014 ; Revised July 20, 2014 ; Accepted July 21, 2014)Key Words: Optical Sensor(광센서), Bobbin Thread(밑실), Single-Channel(단일 채널), Optical-Fiber(광섬유), Quilting Machine(누비기), Embroidery Machine(자수기)초록: 광센서를 이용한 로터리 밑실 감지기를 개발하여 출력 변화에 따른 신호 특성을 분석하였다. 로터리 보빈과 결합되는 광센서 마운트는 ABS(acrylonitrile-butadiene-styrene) resin으로 3D 프린터를 이용하여 형상화하고 로터리 밑실 감지 상태에 따른 출력 변화를 분석하였다. 로터리 밑실 상태에 따라 상대적으로 변화하는 광신호는 충분한 출력신호대비가 관측되어 안정된 제어가 가능하였으며, 이를 통하여 로터리 밑실의 끊김이나 풀림이 효과적이고 신속하게 감지되고 제어되는 방직시스템의 개발이 가능하여 고가원단 손실 감소의 효과를 기대할 수 있다. Abstract: We developed a single-channel thread sensor for a rotary bobbin by optical sensing and analyzed the signal characteristics. A specially designed mount made of ABS (acrylonitrile-butadiene-styrene) resin that encapsulated an optical sensor was fabricated by using a 3D printer and was attached to the rotary bobbin system. Stable control on a weaving machine was achieved by observing the difference in the output signals of an optical sensor system, which vary significantly according to the states of the thread in the weaving operation. The optical sensor effectively detects an unintentional thread cut and run-out during weaving fast enough to enable prompt stopping of the weaving machine, thereby minimizing the loss of expensive fabrics.

Coherent Control of Surface Plasmon Propagation Directions

We have demonstrated the directional control of surface plasmon polariton(SPP) waves through propagating in an asymmetric plasmonic Bragg resonator using femtosecond temporal-phase control via the resonant coupling of SPPs and the interference of SPPs. The near-field images display significant temporal-phase dependence, switching between left and right propagation after the Bragg resonator. Our results would be a key step toward the control of surface plasmon propagation direction in nano-scaled plasmonic applications.

Femtosecond coherent control of surface plasmon propagating direction

We have demonstrated the directional control of surface plasmon polariton(SPP) waves through propagating in an asymmetric plasmonic Bragg resonator using femtosecond temporal-phase control via the resonant coupling of SPPs and the interference of SPPs. The near-field images display significant temporal-phase dependence, switching between left and right propagation after the Bragg resonator.