• Journal of the Korean Magnetics Society
• /
• 제14권6호
• /
• pp.228-231
• /
• 2004

We have studied local magnetization reversal and magnetic properties induced by Laser annealing method in the strip-patterned Ta/NiFe/FeMn/Ta and Ta/NiFe/FeMn/NiFe/Ta multilayers fabricated by ion-beam deposition. The films were exposed to the emission of the DPSS (Diode Pumped Solid State, Nd:YAG) laser under 600 G. The laser beam intensity increased up to 440 mW. When the laser illuminated the patterned film with the power of above 200 m W, the intensity of MR peak located in +87 Oe shrunk. A new MR peak was generated at -63 Oe. When the laser power is 400 mW, the location of positive MR peak(H$\sub$ex/) was changed slightly from +87 Oe to +76 Oe, and the MR ratio was decreased from 0.9% to 0.1 %. On the other hand, the new (negative) MR peak shifted from -63 Oe to -80 Oe, with the MR ratio increased up to 0.3%. As the illuminated area expanded, the intensity of opposite MR peak increased and it of negative MR peak decreased. This proved that the local reversal of exchange biasing should be realized by laser annealing.

• Journal of the Optical Society of Korea
• /
• 제16권1호
• /
• pp.53-56
• /
• 2012

We have developed a slab-type Nd:YAG gain module based on the techniques of conduction cooling and end pumping. The Nd:YAG slab is end-capped on both ends by undoped pure YAG and is pumped through the end-caps by stacked arrays of laser diode bars. The slab's surfaces of total internal reflection are in contact on both sides with microchannel cooling blocks which are cooled by water circulation. The power oscillator based on the gain module generates more than 400 W at 1-kW pumping with a slope efficiency of 55%. The small-signal gain of the gain module is 10 in a single zig-zag pass, and the amplified beam shows a near diffraction-limited beam quality.

• Proceedings of the Optical Society of Korea Conference
• /
• 한국광학회 2000년도 하계학술발표회
• /
• pp.222-223
• /
• 2000

지금까지 gold-coated 반사체, cusp-shaped 반사체, 복합 포물 반사체(CPC), 난반사 공동체 등 다양한 형태의 반사체가 횡펌핑을 이용한 Nd:YAG 레이저의 개발을 위하여 고안되어졌다. 횡여기되는 Nd:YAG 레이저의 광학적 효율은 반사체의 형태, 다이오드 레이저의 파장, Nd:YAG 결정의 지름, Nd$^3$의 도핑농도에 따라 영향을 받는다.$^{(1)}$ 본 연구에서는 고출력의 횡여기 Nd:YAG 레이저를 개발할 목적으로 광여기 공동으로 사용된 난반사 공동체의 내부지름과 레이저 매질인 Nd:YAG 결정의 흡수계수 등 매개변수를 변화시켜 흡수분포와 출력을 계산하였으며, 이러한 매개변수들이 기울기 효율에 미치는 영향을 수치 해석적으로 연구해 보았다. 광선추적법에서 사용한 매개변수 중에서 다이오드 레이저의 파장은 808 nm이고, 반사율은 90%이며, 여기 다이오드 출력은 1080 W이다. 난반사 공동체$^{(2)}$ 의 반사율은 95.7%이고, 결정의 투과율은 90%이며, 결정의 반지름은 2.5 mm이다. 사용된 여기 구조도는 그림 1과 같다. 여기헤드는 Nd:YAG 결정, 난반사 공동체, 그리고 3개의 360 W급 다이오드 어레이들로 구성되어 있다. (중략)

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• 제20권3호
• /
• pp.240-244
• /
• 2007

We investigated the diffraction grating efficiency by the Diode Pumped Solid State(DPSS 532 nm) laser beam wavelength to improve the diffraction efficiency on $As_{40}Ge_{10}Se_{15}S_{35},\;Ag/As_{40}Ge_{10}Se_{15}S_{35}$ and $As_{40}Ge_{10}Se_{15}S_{35}/Ag/As_{40}Ge_{10}Se_{15}S_{35}$ thin film. Diffraction efficiency was obtained from DPSS laser, used (P:P)polarized laser beam on each thin films. As a result, for the laser beam intensity in $0.24mW/cm^2$, single $As_{40}Ge_{10}Se_{15}S_{35}$ thin film shows the highest value of 0.161% diffraction efficiency at 300 s and for laser beam intensity in $2.4mW/cm^2$, it was recorded with the fastest speed of 50 s(0.013%), which the diffraction grating forming speed is faster than that of $0.24mW/cm^2$ beam. $Ag/As_{40}Ge_{10}Se_{15}S_{35}$ double layer and $As_{40}Ge_{10}Se_{15}S_{35}/Ag/As_{40}Ge_{10}Se_{15}S_{35}$ multi-layered thin film also show the faster grating forming speed at $2.4mW/cm^2$ and higher value of diffraction efficiency at $0.24mW/cm^2$.

• Korean Journal of Materials Research
• /
• 제5권7호
• /
• pp.781-785
• /
• 1995

from the $K_{6}$P$_4$ $O_{13}$ flux using a temperature cooling method. According to SHG outpower measurement, phase matching angle is $\theta$=90$^{\circ}$, $\Phi$=23.3$^{\circ}$and angular acceptance of $\Phi$ direction is about 2 degree, Deviation of phase matching angle due to index inhomogeneity in KTP crystal is 0.17 degree. A 20mW green laser was obtained with the combination of a intracavity Nd ; YAG and KTP crystal.

• Journal of Sensor Science and Technology
• /
• 제11권6호
• /
• pp.358-364
• /
• 2002

In this paper, we used U.V.(wavelength, 355nm) laser for adjusting Pt thin films temperature sensor to $100{\Omega}$ at $0^{\circ}C$. Internationally, A-class tolerance of temperature sensor is $0.06{\Omega}$ at $0^{\circ}C$. This is under value of $0.15^{\circ}C$, actually, so high-fine trimming technology is essential to this process. The width of trimmed lines was about $10{\mu}m$ and the best trimming of Pt thin films of $1{\sim}1.5{\mu}m$ was carried out with power : 35mW, rep. rate frequency : 200Hz and bite size : $1.5{\mu}m$. And using photolithography process, 96 resistors were fabricated in $2"{\times}2"$ substrate as the proportion of $79{\sim}90{\Omega}$ and $91{\sim}102{\Omega}$ is 42.7% and 57.3%, respectively. As result of trimming resistors to the target value of $109.73{\Omega}$ at $25^{\circ}C$, 82.3% of resistors had the tolerance within ${\pm}0.30{\Omega}$ and the others(17.7%) were within ${\pm}0.06{\Omega}$ of A-class tolerance.