• Journal of the Optical Society of Korea
• /
• 제7권3호
• /
• pp.160-164
• /
• 2003

Materials processing by ultrashort pulsed laser is actively being applied to micromachining technology due to its advantages with regard to non-thermal machining. In this study, materials processing with ultrashort pulses was studied by using the high repetition rate of a 800 nm Ti:sapphire regenerative amplifier. This revealed that the highly precise micromachining of metallic thin film and bulk glass with a minimal heat affected zone (HAZ) could be obtained by using near damage threshold energy. Grooves with diffraction limited sub-micrometer width were obtained with widths of 620 nm on Cr thin film and 800 nm on a soda-lime glass substrate. The machined patterns were investigated through SEM images. We also phenomenologically examined the influence of variations of parameters and proposed the optimal process conditions for microfabrication.

• 한국세라믹학회지
• /
• 제30권5호
• /
• pp.339-346
• /
• 1993

Inproving laser efficiency, optimum content of Nd3+ which is active ion and effect of Cr3+ as a sensitizer are investigated in 60SiO2.30Li2O.10CaO host glass. The glasses are fabricated with the addition of Nd3+, Cr3+ and then optical properties such as absorption spectrum, fluorescence spectrum and fluorescence lifetime were studied. Finally, lasing efficiency was measured. From this study, optimum content of Nd2O3 appeared to be 3.5wt% and it was observed that the energy absorbed by optical exicitation of the Cr3+ is transfered to the Nd3+. Addition of Cr2O3 tend to improve characteristic of laser oscillation for the laser glass.

• Current Photovoltaic Research
• /
• 제8권1호
• /
• pp.1-5
• /
• 2020

The most important factor in enhancing the performance of an optical device is to minimize reflection and increasing transmittance of light for a broad wavelength range. The choice of appropriate coating material is crucial in decreasing reflection losses at the substrate. The purpose of this review is to highlight anti-reflection coating (ARC) materials that can be applied to silicon solar cell and glass substrate for minimizing reflection losses. The optical and electrical behavior of ARC on a substrate is highly dependent on thickness and refractive index (RI) of ARC films that are being deposited on it. The coating techniques and performance of single and multi-layered ARC films after coated on a substrate in a wide range of wavelength spectrum will be studied in the paper.

• 한국정밀공학회지
• /
• 제24권2호
• /
• pp.58-63
• /
• 2007

This paper proposes a novel method of projecting a multiple stripe pattern whose intensity profile is sinusoidal. The sinusoidal stripe patterns are plated with chromium on a piece of glass, and the glass is placed within an optical projection system. By linearly moving the glass along the direction of the stripe pattern, the projection system generates the motion blurring effect, and as a result, produces a blurred stripe pattern whose intensity profile is sinusoidal along the perpendicular direction of the stripe pattern. The sinusoidal pattern improves the measurement accuracy of phase-shifting method. Experimental results are provided for three different types of stripe patterns: rectangle, diamond, and sinusoid.

• 한국세라믹학회지
• /
• 제27권4호
• /
• pp.521-528
• /
• 1990

Li2O.2SiO2 glass-ceramics were made from the melt by the nucleation and growth treatment. The optimum nucleation temperature and time were determined from DTA curves of as-quenched and thermally treated glasses, and found to be 44$0^{\circ}C$ and 3hrs. The optical microscopic technique was also used to support this result. The volume fractions of crystals present in the partially crystallized specimens were measured using the optical microscopy and the amorphous X-ray scattering methods. The degree of crystallization increased with increasing the crystallization temperature and time. The crystalline phase identified by X-ray diffraction was lithium disilicate. As the crystallinity increased up to 95%, the transmittance of glass-ceramics was decreased linearly. It was also found that for the same heat treatment condition (575$^{\circ}C$, 30min), a thicker specimen showed higher transmittance, presumably due to less crystallinity.

• Transactions on Electrical and Electronic Materials
• /
• 제16권1호
• /
• pp.5-9
• /
• 2015

Optical and electrical properties were studied for Antimony doped tin oxide thin films from precursors containing 10, 30, 50, and 70 atom% of Sb deposited on bare sodalime silica, barrier layer coated sodalime silica, and pure silica glass substrates by sol-gel spinning technique. The direct band gaps were found to vary from 3.13~4.12 eV when measured in the hv range of 2.5~5.0 eV, and varied from 4.22~5.08 eV when measured in the range of 4.0~7.0 eV. Indirect band gap values were in the range of 2.35~3.11 eV. Blue shift of band gap with respect to bulk band gap and Moss-Burstein shift were observed. Physical thickness of the films decreased with the increase in % Sb. Resistivity of the films deposited on SLS substrate was in the order of $10^{-2}$ ohm cm. Sheet resistance of the films deposited on barrier layer coated soda lime silica glass substrate was found to be relatively less.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.1
• /
• pp.216-218
• /
• 2003

The Judd-Ofelt theory is becoming basis that induced of ligand field of electric dipole transitions of between 4f electic states. It is developed for the rare earth ions through judd and of ofelt. This theory be applicate success to the raer earth ions in solid, liquid and gas state. This paper reports a optical characteristices of Nd:glass by using the Judd-Ofelt Method.

• 한국세라믹학회지
• /
• 제52권2호
• /
• pp.146-149
• /
• 2015

Silicate glasses with different $Nd_2O_3$ concentrations were prepared through conventional melt-quenching methods while PbS quantum dots (QDs) were precipitated through heat treatment. The peak wavelengths of absorption and the photoluminescence of PbS QDs shifted to the short-wavelength side as the concentration of $Nd_2O_3$ increased. The electron energy loss spectroscopy (EELS) indicated that $Nd^{3+}$ ions were preferentially distributed inside the PbS QDs instead of the glass matrix. In addition, there was no significant change in the lifetimes of the $Nd^{3+}:^4F_{3/2}$ fluorescence between the as-prepared glass ($607{\mu}s$) and the heat-treated glass($576{\mu}s$). $Nd^{3+}$ ions were surrounded by oxygen instead of sulfur and the Nd-O clusters probably acted as nucleating centers for the formation of PbS QDs inside the glasses.

• 한국레이저가공학회지
• /
• 제17권2호
• /
• pp.19-25
• /
• 2014

Optical embedded diffraction gratings with the bulk modification in BK-7 glass plates excited by tightly focused high-intensity femtosecond (130fs) Ti: sapphire laser (peak wavelength = 790nm) were demonstrated. The structural modifications with diameters ranging from 400nm to $4{\mu}m$ were photo-induced after plasma formation occurred upon irradiation with peak intensities of more than $1{\times}1013W/cm^2$. The graded refractive index profile was fabricated to be a symmetric around from the center of the point at which low-density plasma occurred. The maximum refractive index change was estimated to be $1.5{\times}10^{-2}$. The two optical embedded gratings in BK-7 glass plate were demonstrated with refractive index modification induced by the scanning of low-density plasma formation.

• 한국재료학회지
• /
• 제14권9호
• /
• pp.670-675
• /
• 2004

Glasses in the $Bi_{2}O_3-SiO_2-ZnO$ glasses system were examined as a potential replacement for lead-oxide glass frits with low firing temperature ($500\sim600^{\circ}C$) for the dielectric layer of a plasma display panel (PDP). The glasses were evaluated for glass transition temperature($T_{g}$) and thermal expansion coefficient(${\alpha}$). After forming transparent thick films by a screen-printing method, it was evaluated for the optical properties. The transmittance of thick films fired at $500-600^{\circ}C$ showed above $80\%$, which was not dependent on the firing temperature. As a result, many pores were observed at samples fired at low temperature, while the number of pores from samples prepared at high temperature decreased and the pores size increased.