• Current Optics and Photonics
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• 제7권2호
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• pp.127-135
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• 2023

Radially polarized beams with the ability to generate a sub-wavelength sized spot in a longitudinal field provides significant applications in microscopic imaging, optical tweezers, lithography and so on. However, this excellent property can also be achieved based on conventional circularly polarized beams. Here, we demonstrate its ability to create a strong longitudinal field by comparing the tight focusing characteristics of fractional-order vortex modulated radial polarized and left-handed circular polarized Bessel-Gauss beams. Additionally, the possibility of generating arbitrary fractional-order vortex modulated Bessel-Gauss beams with a strong longitudinal field is demonstrated. A special modulation method of left-handed circularly polarized Bessel-Gauss beams modulated by a fractional-order vortex is adopted creatively and a series of regulation laws are obtained. Specifically, the fractional-order phase modulation parameter n can accurately control the number of optical lobes. The ratio of the pupil radius to the incident beam waist β₁ can control the radius of the optical lobes. The first-order Bessel function amplitude modulation parameter β₂ can control the number of layers of optical lobes. This work not only adds a new modulation method for optical micromanipulation and optical communication, but also enriches the research on fractional vortex beams which has very important academic significance.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 추계학술대회 논문집 전기물성,응용부문
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• pp.128-130
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• 2001

In this study, we investigate the deposition characteristics of merocyanine dye(MD) Langmuir-Blodgett(LB) film using quartz crystal microbalance (QCM). The MD optical system mixed with fatty acid was fabricated using LB method. And their optical characteristics were investigated using UV spectroscopy. The optical behavior of MD LB film was investigated asto thermal treatment. The resonant frequency and admittance was measured during dissociation of J-aggregate of MD LB film. As a result, it has been suggested that the J-aggregate dissociation in MD LB film by thermal treatment give rise to transformation of oscillation characteristics of quartz crystal.

• 전기학회논문지
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• 제58권8호
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• pp.1580-1584
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• 2009

We have theoretically analyzed the monolithic integration of vertical cavity lasers with depleted optical thyristor (VCL-DOT) structure and experimentally demonstrated optical logic gates such as AND-gate, OR-gate, and INVERTER implemented by VCL-DOT for an optical programmable gate array. The optical AND and OR gates have been realized by changing a input bias of the single VCL-DOTs and all kinds of optical logic functions are also implemented by adjusting an intensity of the reference input beams into the differential VCL-DOTs. To achieve the high sensitivity, high slope efficiency and low threshold current, a small active region of lasing part and a wide detecting area are simultaneously designed by using a selective oxidation process. The fabricated devices clearly show nonlinear s-shaped current-voltage characteristics and lasing characteristics of a low threshold current with 0.65 mA and output spectrum at 854 nm.

• ETRI Journal
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• 제30권6호
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• pp.833-843
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• 2008

The effect of forward and reverse electrostatic discharge (ESD) on the electro-optical characteristics of oxide vertical-cavity surface-emitting lasers is investigated using a human body model for the purpose of understanding degradation behavior. Forward ESD-induced degradation is complicated, showing three degradation phases depending on ESD voltage, while reverse ESD-induced degradation is relatively simple, exhibiting two phases of degradation divided by a sudden distinctive change in electro-optical characteristics. We demonstrate that the increase in the threshold current is mainly due to the increase in leakage current, nonradiative recombination current, and optical loss. The decrease in the slope efficiency is mainly due to the increase in optical loss.

• Journal of the Optical Society of Korea
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• 제17권3호
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• pp.242-248
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• 2013

Full color holographic optical element fabrication using a photopolymer is proposed for a waveguide-type head mounted display. The fabricated full color holographic optical elements can be attached to the waveguide to replace the conventional couple-in and couple-out optics in the head mounted display. To implement the system, this study analyzed the optical characteristics of the photopolymer using three lasers (red, green and blue). Considering the color uniformity, a new laminated structure for a full color holographic optical element was also designed. The proposed system was confirmed experimentally.

• 한국전기전자재료학회논문지
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• 제11권8호
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• pp.637-645
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• 1998

The characteristics of waveguide, electrode and packaging fabricated for acousto-optic tunable filters(AOTF) used for optical communications were analyzed. A $Ti:LiNbO_3$in-diffusing method was employed for the formation of the optical waveguide with a dimension of width $8{\mu}m$, length $30000-50000{\mu}m$ and varying the thickness. The diffusion was carried at $1050^{\circ}C$ for 8 hours to pattern the optical waveguide. The resulted waveguide exhibited a single mode at 1550nm optical wavelength. The width of IDT, with 10 SAM periods, was $5000{\mu}m$ . Impedances of the electrodes deposited with Au were analyzed using a network analyzer; $48.1\Omega$ at the center frequency of 193MHz for electrode thickness of $1500{\AA}$ and $50.7\Omega$ at the center frequency of 192MHz for $1600\AA$. And the characteristics of packaged AOTF was analyzed. When the electrical frequency 177.1MHz was applied to the device, the mode conversion efficiency was measured as 63% at the optical wavelength 1515nm.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 추계학술대회 논문집 전기물성,응용부문
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• pp.136-138
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• 2005

Merocyanine dye (MD) has been extensively investigated due to its marked potential application to photo-electric devices. We fabricated the number of layers to control its optical characteristics using the Langmuir-Blodgett (LB) method. We evaluated the morphology and optical characteristics of MD LB films using Atomic Force Microscopy (AFM) and UV spectroscopy, PL spectroscopy. As a result, we obtained the quantitative morphology and optical characteristics of LB films from controlling the deposided layers.

• 조명전기설비학회논문지
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• 제25권7호
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• pp.1-8
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• 2011

The high efficiency tubular LED lamp has been developed. But, it occurs optical losses in consists of LED package, module, diffuser etc.. By Measuring the tubular LED lamp's luminous flux, we compared and analyzed about the effect of optical losses for each component and actually using measured luminous intensity distribution data, illuminance distribution was simulated by Relux. Optical losses are 24[%] from LED package to luminaire and the tubular LED lamp can be replaced with fluorescent lamp. In this paper, we could provide data for optimum lighting design by analyzing the optical characteristics for developing and propagating the tubular LED lamp.

• E2M - 전기 전자와 첨단 소재
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• 제9권5호
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• pp.445-449
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• 1996

Structural and optical characteristics in Se thin film fabricated by EBE method had been studied. Se thin film was deposited with noncrystalline until substrate temperature of >$100^{\circ}C$ Color of its surface had red genealogy, and its optical energy band gap was about 2.45 eV. But Se film was grown with monoclinic at substrate temperature of over >$150^{\circ}C$ Also, color of its surface had gray genealogy, and its optical energy band gap was about 2.31 eV. Finally, after heat-treatment at >$150^{\circ}C$ for 15 min with substrate temperature of >$100^{\circ}C$ noncrystalline Se was proved to be hexagonal, and color of its surface had dark gray genealogy, and its optical energy band gap was about 2.06 eV. From the results, it was known that Se thin film for photoelectric device with the lowest optical energy band gap was accepted from hexagonal structure.

• 한국전기전자재료학회논문지
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• 제18권6호
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• pp.576-581
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• 2005

We fabricated red organic light emitting diodes(OLEDs) utilizing tis(8-hydroxyquinoline) aluminum $(Alq_3)$ doped with $5\%$ of (4-(dicyanomethylene)-2-i-propyl-6-(1,1,7,7-tetramethyljulolidyl-9-enyl)-4H-pyran) (DCJTI) and investigated the driving and modulation characteristics for applying to the electro-optical conversion device. To improve the driving characteristics of red OLEDs, 3 V of offset voltage, which is equal to the turn on voltage, Is applied to the device. Offset voltage enhanced the optical EL output and reduced the rise time of EL waveforms of red OLEDs, and hence the cutoff frequency is increased with increasing applied voltage. The optical pulse of 100 MHz has been obtained from red OLEDs. Therefore, we confirmed that the red OLEDs can be applied to the fields of optical communication as an electro-optical conversion device.