반도체 레이저로 펌핑하는 능동형 Q-스위칭된 1525 nm YVO$_4$-Nd:YVO$_4$-YVO$_4$ 자체 라만 레이저

김규욱,추한태,박차곤,최진혁,권도환 한국물리학회 2017 새물리 Vol.67 No.4

파장이 808 nm인 반도체 레이저로 YVO$_4$-Nd:YVO$_4$-YVO$_4$ 복합 결정을 펌핑하여 1342 nm를 발진시키고 음향광학 효과를 이용하여 능동형 Q-스위칭시켰다. Q-스위칭된 1342 nm의 레이저 빔을 동일한 레이저 결정 내에서 자체 라만 과정을 통하여 1525 nm로 변환하여 발진시키고 출력 특성을 조사하였다. 반도체 레이저 출력이 20 W이고, Q-스위칭 반복률이 30 kHz일 때 1525 nm의 최대 출력은 980 mW, 펄스폭은 25 ns이었다. 이로부터 반도체 레이저가 1525 nm로 변환되는 효율은 약 4.9\%이고, 출력 기울기 효율은 6.0\%로 측정되었다. 이때 펄스 하나당 에너지는 약 32.7 $\mu$J이고, 첨두 출력은 1.3 kW이었다. We constructed an actively Q-switched YVO$_4$-Nd:YVO$_4$-YVO$_4$ laser pumped by using an 808 nm laser diode. We converted a Q-switched 1342 nm laser into a 1525 nm laser by using a self Raman process in the same YVO$_4$-Nd:YVO$_4$-YVO$_4$ laser crystal. We also investigated the output characteristics of the 1525 nm Raman laser. As a result, we found that the 1525 nm laser had an output power of 980 mW and a pulse width of 25 ns at a repetition rate of 30 kHz with a laser-diode power of 20 W. The conversion efficiency of the pumping laser into 1525 nm and the slope efficiency were measured to be 4.9\% and 6.0\%, respectively. Also, the single-pulse energy and its peak power were measured to be 32.7 $\mu$J and 1.3 kW.

능동형 Q-스위칭된 1175 nm Nd:YVO$_{4}$ 자체-라만 레이저

김규욱,추한태,박차곤,이건희 한국물리학회 2016 새물리 Vol.66 No.3

The output power characteristics of the acousto-optically Q-switched and first-Stokes-shifted 1175 nm Nd:YVO$_{4}$ self-Raman laser pumped by using a diode laser were investigated. A maximum Raman output power of 1.8 W was achieved at a Q-switched pulse repetition rate of 30 kHz with an incident pump power of 22.4 W. The optical conversion efficiency from the diode laser to the Raman laser and the output power slope efficiency were 8% and 7.4%, respectively. A minimum pulse width of 14 ns was measured at a Q-switched pulse repetition rate of 20 kHz with an incident pump power of 22.4 W, corresponding to the highest pulse energy and the highest peak power of 47 $\mu$J and 3.3 kW, respectively. 다이오드 레이저로 펌핑하고 광-음향 변조기를 이용하여 능동형 Q-스위칭된 제1차 스토크스 변환된 1175 nm Nd:YVO$_{4}$ 자체-라만 레이저의 출력 특성을 조사하였다. Q-스위칭 펄스 반복률이 30 kHz에서 22.4 W의 입사 펌프 파워 일 때, 최고 1.8 W의 라만 출력을 얻어, 다이오드로 레이저로부터 라만 레이저로의 광 변환 효율 및 출력 기울기 효율이 각각 8% 및 7.4% 이었다. 최소의 펄스폭은 Q-스위칭 펄스 반복률이 20 kHz에서 24.1 W의 입사 펌프 파워 일 때 14 ns로 측정되었고, 이때의 최대 펄스 에너지 및 최대 피크 파워는 각각 47 $\mu$J 및 3.3 kW이었다.

두 개의 초점을 갖는 Ti: Sapphire 레이저 공진기의 안정성에 대한 고찰

김규욱 國立金烏工科大學校附設生産技術硏究所 1997 産業技術開發硏究 Vol.13 No.-

An analysis of Ti:sapphire laser cavity with two foci is made using a conventional cavity reduction technique and optimal mirror separations, beam waist and focal positions are calculated.

레이저 증폭기에서 펄스 증폭 계산

김규욱 金烏工科大學校 1997 論文集 Vol.18 No.-

The Frantz-Nodvik equation is simple but convenient tool to understand the characteristics of pulse propagation in a laser amplifier. In this paper, the calculational results of the characteristics of fs pulse propagation in an XeCl laser amplifier are described. Especially, the pulse width of the output pulse from an XeCl laser amplifier is investigated assuming the input pulse form to be square-top, sech², Gaussian, and modified Gaussian whose rising time of front part is shorter than that of Gaussian. As the product of gain and length, g*l, is increased, the FWHM of output is always increased for Sech², and Gaussian, but it is always decreased for square-top. In the case of modified Gaussian, the width of output pulse is decreased when g*l is quite small, but increased again as the g*l is increased.

LDV를 이용한 유체의 방향 결정 ( Determination of Flow Direction by Using as Acousto-Optic Effect )

김규욱,최종운,원종욱 대한전자공학회 1990 대한전자공학회 학술대회 Vol.1990 No.1

1.57 μm로 발진하는 Nd:YAG/KTP 내부 공진기형 광파라메트릭 발진기의 구성과 출력 특성

김규욱,추한태,박차곤,이건희 한국물리학회 2015 새물리 Vol.65 No.3

파장이 808 nm인 반도체 레이저로 펌핑하는 Nd:YAG 레이저를 음향광학 효과를 이용하여 능동형 큐 스위칭시켰다. 큐 스위칭된 1064 nm의 레이저 빔을 KTP 비선형 결정을 이용한 내부 공진기형 광파라메트릭 발진기에 입사시켜서 1.57 μm 레이저로 변환시켰다. 펌핑 레이저의 출력, 큐 스위칭시키는 주파수 변화 등에 따른 1.57 μm 레이저의 출력 특성을 조사하였다. 그 결과 반도체 레이저의 출력이 16.5 W, 동작 주파수가 16 kHz 일 때 1.57 μm의 OPO 출력은 250 mW이어서 펌핑 레이저가 1.57 μm 로 변환되는 효율은 약 1.52%이고, OPO 펄스 하나당 에너지는 약 15.6 μJ이었다. We constructed an acousto-optically Q-switched Nd:YAG laser pumped by a 808 nm laser diode. We converted a Q-switched 1064 nm laser into a 1.57 μm laser by using an intracavity optical parametric oscillator with a KTP nonlinear crystal. We also investigated the output characteristics of the 1.57 μm laser as functions of the pumping laser’s power and the Q-switching frequencies. As a result, we found that the 1.57 μm laser had an output power of 250 mW when the laser diode had a power 16.5 W and a frequency of 16 kHz. Also, the conversion efficiency of the pumping laser to 1.57 μm and the single pulse energy of the OPO were measured to be 1.52% and 15.6 μJ, respectively.

광음향 변조기를 이용한 유체의 방향결정

김규욱,최종운,원종욱 한국광학회 1990 한국광학회지 Vol.1 No.1

광음향 변조기를 사용하여 전방산란 이중광속 LDV를 구성하고 유리관 속을 흐르는 물의 방향을 조사하였다. 하나의 레이저 빔을 40MHz로 변조시킬 때 회절된 빔의 차수 및 유체의 방향에 따라서 이동된 Doppler 신호의 주파수를 측정함으로써 유체의 방향을 결정하였다. 또한 LDV 장치의 검출기에서 검출된 고주파 신호를 증폭하기 위하여 대역폭이 0-300MHz이고 이득이 38dB인 증폭회로를 설계 제작하였다. The flow direction in a glass tube is measured by using a forward scattering dual beam laser Doppler velo$.$ cimeter with an acousto-optic modulator. We can determine the flow direction by measuring the shifted Doppler frequency which is dependent on the order of modulation of the laser beam and the fluid flow direction. Also. an electronic amplification circuit which has a bandwidth of 0 . 300 MHz and a gain of 38 dB is designed and fabricated to amplify the high frequency signal.signal.

1GW 광분해 옥소 레이저 빔으로 발생시킨 플라즈마의 특성 ( Characteristics of the Plasma Produced by 1GW Iodine Photodissociation Laser Beam )

김규욱,김동환,이상수 대한전자공학회 1988 대한전자공학회 학술대회 Vol.1988 No.1

국내 양돈장의 차단방역 수준에 대한 역학적 연구: 돼지생식기호흡기증후군 위험요인 분석

김규욱,박선일 한국임상수의학회 2015 한국임상수의학회지 Vol.32 No.1

Although researches have highlighted the important role of enhanced farm biosecurity to reduce the severity and prevalence of diseases in livestock, to date there has been little study in Korea on farmers’ adoption of biosecurity measures to control porcine reproductive and respiratory syndrome virus (PRRSV) infection. To mitigate the risk of PRRSV infection in pigs, the risk factors by which PRRSV is introduced in pig farms must be determined. The primary aim of this study was to investigate pig producers’ perceptions about on-farm biosecurity practices. We also analyzed data obtained from a cross-sectional study on 196 farrow-to-finish farms conducted between March 2013 and February 2014 to identify risk factors for PRRSV infection at farm level. Standardized questionnaires with information about basic demographical data and management practices were collected in each farm by on-site visit of trained veterinarians. Farms were classified as negative or positive through the use of infection profiles that combined data on PCR positive pigs and serological testing including antibody titer, sero-conversion pattern at each age category, and vaccination status. Data on biosecurity practices, farm management and environmental characteristics were analyzed using multivariate ordinal logistic regression. Generally, the biosecurity level in the pig farms included in this study were insufficient to reduce/prevent the risk of PRRSV infection given the high pig density areas and the considerable extent of vehicle movement. Factors associated with PRRSV infection were those where owners used on-farm vaccination programs had a lower risk of infection (OR = 0.19, 95% CI 0.06-0.61). The results from the analysis may guide to tailor biosecurity measures in the reduction or prevention of PRRS to the specific circumstances of pig farms in different localities of the world. To the best knowledge of the authors, this is the first study to report information on the biosecurity practices currently implemented on Korean pig farms.

듀이의 경험이론에 비추어 본 도구주의의 재해석 - 교육목적론의 정립을 위하여 -

김규욱 한국교육원리학회 1996 교육원리연구 Vol.1 No.1