적외선 영역에서 광대역으로 파장 가변되는 연속 발진 Cr⁴+ : YAG 레이저 개발

추한태(Han Tae Choo),이봉연(Bong Yeon Lee),양준묵(Joon Mook Yang),이동한(Dong Han Lee),임기수(Ki Soo Lim),이치원(Chi Weon Lee) 한국광학회 1999 한국광학회지 Vol.10 No.3

연속 발진 Nd:YAG 레이저를 펌핑 광원으로 하여 보다 조밀하고 견고하며, 안정된 연속 발진 파장 가변 Cr⁴+:YAG 레이저를 개발하여 레이저 출력 특성, 파장 가변성 및 발진 레이저 선폭 등을 조사하였다. 공진기 구조는 공진기 안정 조건을 계산하여 비점수차가 보상된 Z 자형 접힘 공진기를 구성하였다. 공진기 출력 거울의 투과율이 1%일 때, 결정의 온도를 20℃로 유지하며 6 W로 펌핑하였을 경우, 중심 파장이 1.45 ㎛에서 최대 400 mW의 평균 출력을 갖는 매우 안정된 연속 발진 Cr⁴+:YAG 레이저를 얻을 수 있었으며, 출력 기울기 효율은 8%였다. 또한 공진기 내에 복굴절 필터를 삽입하여 1.399 ㎛에서 1.532 ㎛까지의 파장 가변 영역을 얻었고, 1.4903 ㎛에서 최대 340 mW의 평균 출력을 얻을 수 있었으며, 이때의 레이저 발진 선폭은 0.21 ㎚였다. We have investigated the output power performance of a continuous-wave chromium-doped YAG laser (Cr⁴+: YAG laser), pumped by a Nd : YAG laser. With an output coupler of 1% transmission, we obtained as much as 400 mW of the average output power at 1.450 ㎛. The power slope efficiency of 8%, when the gain medium was cooled to 20℃. We tuned the wavelength of the Cr+⁴: YAG laser, at pump power of 6 W, by using birefringent filter. As a result, lasing wavelength was tuned from 1.399 ㎛ to 1.532 ㎛, with the maximum output power of 340 mW at 1.4903 ㎛ and the linewidth was 0.21 ㎚.

고속고압 방전간극을 사용한 질소 레이저의 동작 특성

양준묵,이치원,안근옥 충남대학교 자연과학연구소 1987 忠南科學硏究誌 Vol.14 No.2

We have constructed a nitrogen laser which is 42㎝ long has a rapid high-voltage spark gap and a multiple parallel capacitor-type Blumlein transmission line circuit, whose total capacitance is about 80 nF. The maximum output power of laser has obtained under the condition of nitrogen gas pressure of 80torr, spark gap spacing of 2.26mm and charging voltage of 10.5kV. Under these optimum conditions and maintaining constant stability of 0.02, this laser can be operated with a range of repetition rate, from 10 to 30.1 Hz. The value of E/P is 437 V.cm^-1. torr^-1 for maximum output power and 417 Vcm^-1. torr^-1 for optimum stability condition.

나선형 이중 평행판 축전기형 Blumlein 전송회로를 사용한 소형 질소레이저의 동작 특성 연구

양준묵,이치원,조돈수,이봉연 충남대학교 기초과학연구소 1995 忠南科學硏究誌 Vol.22 No.1

The design and performance of a compact nitrogen laser which consists of a Spiral multiple parallel plate capacitor type Blumlein transmission line circuit are described. The laser tube is made by 50 ㎜ long with a 2.5 ㎜ main electrode gap spacing. The output power increased with the spark gap distance. The peak power of 3.0 μJ has been obtained with a spark gap distance of 3.5 ㎜ and a repetition rate of 30㎐. The optimum nitrogen gas pressure was about 60torr independent of the variation of spark gap distance. The laser operates with repetition rate of up to 70 ㎐.

二重 傳送回路를 사용한 窒素 레이저의 特性

梁俊默,李致遠 충남대학교 자연과학연구소 1984 忠南科學硏究誌 Vol.11 No.2

We have studied on the economic construction and operational characteristics of the nitrogen laser. The laser tube is 66㎝ long with variable electrode-gap-spacing coupled to the transmission line circuit. This transmission line circuit is assembled with tow sets of Blumline transmission line circuits, which we call the double transmission line circuit. Each transmission line circuit consits of 3 sheets of 0.188㎜ mylar films and 4 sheets of aluminum foils. the optimum operational conditions of this nitrogen laser are 80torr in nitrogen gas pressure and 6500volts in voltage. In this conditions, we have measured that, repetition rate is 21㎐,the stability of the optical power is 70% and E/p is 270 volts /㎝-torr which was measured to be 2.5 times as large as that of the othe reports so tar.

다극형 스파크 �b과 다중평행판 축전기형 전송회로를 사용한 질소레이저의 동작특성

장철용,박영수,양준목,이치원 충남대학교 기초과학연구소 1994 忠南科學硏究誌 Vol.21 No.1

We have studied on the operational characteristics of a nitrogen laser which was coupled with a multiplex parallel capacitor type Blumlein transmission line circuit and a multiplex sparkgap. This spark gap consisted of 8 pairs of electrode and was 50 ㎝ in length, as long as the laser tube. According to increasing the number of electrodes in the spark gaps up to the 6 pairs, the output power and stability of the laser was increased. It was to be improved that the multiplex spark gap was operated as a good peformance to the nitrogen laser system. The optimum operational condition of the nitrogen laser at 20㎐ of repetition rate could be obtained with the nitrogen gas pressure of 80 torr, E/P value of 325.0 v/㎝ torr at the electrodes spacing 5.0 ㎜ and of 90 torr, E/P value of 311.1 v/㎝ torr at the electrodes spacing 6.0 ㎜ respectively.

기체온도 변화에 따른 질소레이저의 출력특성

김성훈,양준묵,추한태,이치원 충남대학교 자연과학연구소 1993 忠南科學硏究誌 Vol.20 No.2

While the temperature of the gas was being changed by modifying the value of E/P which being effects the output characteristics of gas laser into a temperature function, the optimum value of E/P was calculated, being applied to Nitrogen laser and was compared with experimental values. The optimum operational characteristics by the variation of the nitrogen gas temperature is observed at 30 ℃ in gas temperature and 120 torr in gas pressure. Also the value of E/P is evaluated to be 423 V ㎝^-1torr^-1 which is 2.2 times as large as that of theoretical value. According to increasing the nitrogen gas temperature, the nitrogen gas pressure for the laser action is to be broaded. However in this case, the maximum output power is slightly decrease.

Blumlein 전송회로에 의해 선전리되는 질소레이저의 동작특성 연구

양준묵,추한태,이봉연,이치원 충남대학교 1990 忠南科學硏究誌 Vol.17 No.2

The design and construction of nitrogen laser preionized with a Blumlein transmission line circuit is described. For the power supply, we have used a pulse type high voltage power source that can be produce 10 joule energy in a pulse. The condition of maximum output power is observed at N_2 gas pressure of 100 torr, spark gap distance of 6.0 mm, repetition rate of 30Hz with preionization, and the stability increases by 0.7%. The maximum increment of output power is achieved at pressure of 200 torr when preionization is used. Finally we can increase the output power by approximately 60% by using this work, and the E/P value is 133 V㎝^(-1) torr^(-1).

압박 고 나사와 6 공 이상의 금속판을 이용한 대퇴골 전자 주위 불안정 골절의 치료

문명상,이정웅,선두훈,이치원 대한골절학회 2001 대한골절학회지 Vol.14 No.4

Purpose: The objectives of this study are to observe and report the clinical results of the treatment of unstable pertrochanteric femur fracture extending into subtrochanter or shaft of the femur using compression hip screw and plate with 6 or more holes. Materials and Methods: Between February 1993 and December 1997, 39 patients were treated surgically for unstable pertrochanteric femur fracture. 26 patients who have been followed up over twelve months were included in this study. Surgery was performed within 2 weeks after injury, except one patient who had combined head injury. The fracture was fixed internally with compression hip screw and plate with 6 or more holes, and additional fixations were also performed with Cable wire, interfragmentary screw and Knowles pin. The results was analyzed radiographically and clinically for blood loss, surgery time, bony union period and complication. Average estimated blood loss was 910 cc. Average surgery time was one hundred ten minutes. The complications occurred in 7 cases (27%); 1 nonunion, 2 screw loosening and 4 cases of superficial wound infection. There was no case of lag screw penetration to the femoral head or metal failure. The bony union was obtained at average 22 weeks. Conclusion: With use of the compression hip screw and long plate with 6 or more holes for stable internal fixation, we obtained satisfactory results for unstable pertrochanteric femur fracture extending into subtrochanter or shaft of the femur.