• Korean Journal of Optics and Photonics
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• v.28 no.1
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• pp.9-15
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• 2017

We precisely measured and analyzed the dynamics of peptide-antibody interactions, using an ellipsometric biosensor based on a silicon substrate. To reduce the signal error due to the imperfect flatness of the substrate for extremely low concentrations of peptide, we fabricated the biosensor with a silicon substrate coated with Dextran SAM, instead of a glass prism coated with a thin metallic thin film. At an injection speed of $100{\mu}l/min$ of buffer liquid, we detected the dynamics of antibody-Dextran SAM or peptide-antibody fixed on biosensor, respectively. We detected the dynamics of antibody-Dextran SAM interactions down to a low concentration of 5 ng per liter, and we precisely measured the dynamics of association and dissociation of peptide and antibody down to 100 nM of peptide. We obtained the rate constants for association and dissociation from fitting the data by using deduced dynamical equation. As a result, we obtained an equilibrium constant for dissociation of 97 nM of peptide-antibody complex, which belongs to Class I.

• Korean Journal of Optics and Photonics
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• v.13 no.4
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• pp.363-369
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• 2002

We have designed conductive transparent filters using a low-emissivity coating such as [dielectric|Ag|dielectric] for display applications. The design is the repetition of [$TiO_{2}$|Ti|Ag |$TiO_{2}$] to increase the transmittance in the visible and decrease the transmittance in the near IR. The conductive transparent filters are deposited by a radio frequency(RF) magnetron sputtering system. The optical, structural and electrical properties of the filters were investigated and the optical spectra are compared with simulated spectra. The thickness of the deposited Ag films is above 13 ㎚ to increase the conductivity and that of $TiO_{2}$ films is 24 ㎚ to increase the transmittance in the visible range. Ti blockers are employed to prevent the Ag films from being oxidized by an oxygen gas during the reactive sputtering process. Also, it is shown that the thicker Ti film is necessary as the period increases. Finally, a filter with repetition of the basic structure three times shows the better cut-off near infrared(NIR) and the sheet resistance as low as 2Ω/□ which is enough to shield an unnecessary electromagnetic waves for a display panel.

• Korean Journal of Optics and Photonics
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• v.11 no.5
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• pp.323-329
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• 2000

In this study we have calculated an ideal complex refractive index of a TiN trim used in a layer of anl1reilecnon (I\R) coatmg, [air$ISiO_2ITiNIglass$] in the visible. Also we simulated the rellectance of lwo-layer AR coating by varying the thicknesses of TiN and $SiO_2$ layers, respecl1vely. The simolation results show that we can controllhe lowest reflectance and AR band of tile AR coating. The TIN fihns were fabricated by a RF magnetron sputtering apparalus. The chemical, structural and electrical properties of TiN fih11S were inveshgated by the Rutherford backscattering spech'oscopy (RBS), atomic force microscope (AFM) and 4-point probe. The optical properlies were inve,tigated by the spectrophotometer and vanable angle spectroscopic ellipsometer (VASE). The smface roughness of TiN flhns \vas $9~10\AA$. TIle resistivity of TiN films was TEX>$360~730\mu$\Omega $ cm. The ,toichlOllletry of TiN film was 1'1: O:N = I: 0.65 :0.95 and ilic oxygen wa~ found on ilie smface. With these experimental and simu]al1on resulLs, we deposited duo: two-layer AR coating, [air$ISiO_2ITiNIglass$] and the refleClance was under 0.5% ill the regIOn of 440-650 run. 0 run.

• Korean Journal of Optics and Photonics
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• v.23 no.1
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• pp.12-16
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• 2012

In the paper, we fabricated a Ni master with $45^{\circ}$-mirror structures for flexible waveguide fabrication. The flexible waveguide films with embedded $45^{\circ}$-angled mirrors at the waveguide ends were successfully fabricated using a UV-imprint process. Next, in order to enhance the reflectivity of the mirrors, Ni(3 nm)-Au(200 nm) bilayers were evaporated on the $45^{\circ}$-angled facets through a locally opened thin mask using an electron beam evaporator. We measured propagation loss, bending loss, mirror loss and bending reliability of the fabricated waveguide.

• Korean Journal of Optics and Photonics
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• v.28 no.2
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• pp.59-67
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• 2017

This paper proposes an asymmetric split-loop resonator with an outer square loop (ASLR-OSL), which can actively control terahertz wave transmission properties while maintaining a high-Q-factor of the asymmetric split-loop resonator (ASLR). An added outer square loop is designed to play the roles of both a metamaterial and a micro-heater, which can control the temperature through a directly applied bias voltage. A vanadium dioxide ($VO_2$) thin film, which exhibits an insulator-metal phase transition with temperature change, is used to control the transmission properties. The proposed ASLR-OSL shows transmission properties similar to those of the ASLR, and they can be successfully controlled by directly applying bias voltage to the outer square loop. Based on these results, an electrically controllable terahertz high-Q metamaterial could be achieved simply by adding a square loop to the outside of a well-known high-Q metamaterial.

• Korean Journal of Optics and Photonics
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• v.16 no.4
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• pp.384-391
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• 2005

A polymer optical microring resonator, which is laterally coupled to a straight bus waveguide, has been proposed and demonstrated using a nanoimprint technique. The propagation loss of the ring waveguide and the optical power coupling between the ring and bus waveguides was calculated by using a beam propagation method, then the dependence of the device performance on them was investigated using a transfer matrix method. We have especially introduced an imprint stamp incorporating a smoothing buffer layer made of a silicon nitride thin film. This layer played an efficient role in improving the sidewall roughness of the waveguide pattern engraved on the stamp and thus reducing the scattering loss. As a result the overall Q factor of the resonator was greatly increased. Also it reduced the gap between the ring and bus waveguides effectively to enhance the coupling between them, without relying on the direct writing method based on an e-beam writer. As for the achieved device performance at the wavelength of 1550 nm, the quality factor, the extinction ratio, and the free spectral range were ~103800, ~11 dB, and 1.16 m, respectively.

• Korean Journal of Optics and Photonics
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• v.13 no.5
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• pp.455-459
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• 2002

The transport and optical properties of $In_2O_3$:Zn(IZO) thin films grown by DC magnetron sputtering deposition have been studied. The deposition temperatures ($T_s$) were varied from room temperature to $400^{\circ}C$ in $50^{\circ}C$ steps. The IZO films are an amorphous phase for $T_s$<$300^{\circ}C$ and polycrystalline phase for $350^{\circ}C$＜$T_s$. In contrast to ordinary films, amorphous IZO films have lower resistivity and higher optical transmittance than polycrystalline IZO films. The resistivity of amorphous IZO was in the range of 0.29~0.4 m$\Omega$cm and that of polycrystalline IZO was in the range of 1~4 m$\Omega$cm. The carrier type for IZO film was found to be n-type, and the carrier density, was $3~5{\times}10^{20}/cm^3$. The Hall mobility, $({\mu}_H)$, was 20~$50\textrm{cm}^2$/V.sec. The predominant scattering mechanisms in both amorphous and polycrystalline IZO films were believed to be ionized impurity scattering and lattice scattering. The visible transmittance of the IZO films, which decreases with an increase of TS, was above 80%.

• Journal of Korean Ophthalmic Optics Society
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• v.13 no.1
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• pp.53-58
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• 2008

Purpose: To design and fabricate the small sputter coating system for the Ophthalmic lens. Methods: The design of sputter target was done using macleod program for AR coating and mirror coating of Ophthalmic lens with Si target and then the sputter system was fabricated. Results: The optimum condition of AR coating with Si target was [air|$SiO_2$(81.3)|$Si_3N_4$ (102)|$SiO_2$(19.21)|$Si_3N_4$(15.95)|$SiO_2$(102)|glass], for blue color mirror coating [air|$SiO_2$(56.61)|$Si_3N_4$(135.86)|$SiO_2$(67.64)|$Si_3N_4$(55.4)|$SiO_2$(53.53)|$Si_3N_4$(51.28)|glass], for green color coating [air|$SiO_2$(66.2)|$Si_3N_4$(22.76)|$SiO_2$(56.58)|$Si_3N_4$(140.35)|$SiO_2$(152.35)|$Si_3N_4$(70.16)|$SiO_2$(121.87)|glass], for gold color [air|$SiO_2$(83.59)|$Si_3N_4$(144.86)|$SiO_2$(11.82)|$Si_3N_4$(129.93)|$SiO_2$(90.01)|$Si_3N_4$(88.37)|glass]. Conclusions: In the fabrication of sputtering coating apparatus, Dual cathode with same Ti target were coated at the same time on both sides of Ophthalmic lens to lessen the time of coating on Ophthalmic Lens and save the cost of the lens. The distance of target-substrate of cathode was variable from 12.5 cm to 20 cm. Turbo pump was used to take the whole coating process about 15 min. instead of diffusion pump. The lens holder was made to coat 2 pairs lens every coating and was rotated to get the uniformity of thin film.