서지주요정보
導波管型 炭酸가스 레이저의 高周波 勵起에 관한 硏究 = Radio frequency characteristics of a waveguide $CO_2$ laser
서명 / 저자 導波管型 炭酸가스 레이저의 高周波 勵起에 관한 硏究 = Radio frequency characteristics of a waveguide $CO_2$ laser / 김윤명.
저자명 김윤명 ; Kim, Yoon-Myung
발행사항 [대전 : 한국과학기술원, 1990].
Online Access 제한공개(로그인 후 원문보기 가능)원문

소장정보

등록번호

8001483

소장위치/청구기호

학술문화관(문화관) 보존서고

DEE 9022

SMS전송

도서상태

이용가능

대출가능

반납예정일

초록정보

The conventional high power $CO_2$ laser systems make use of high voltage DC for the excitation of the medium, and the light propagates in the free space between the two mirrors of the resonator. The light can travel back and forth along a hollow narrow tube, however, with greater frequency differences between neighboring transverse modes, which gives inherent stability of the resonator with permanent mirror alignments. One of the possible excitation of $CO_2$ laser medium is by radio frequencies (RF). With the advent of high frequency power semi-conductor devices it is possible to make light weight and small RF source for laser pumping. The higher frequency produces the higher efficiency and the lower sustaining voltage. As the frequency increases, the RF standing wave voltage variation along the optical waveguide rises, though. This paper analyzes the incident and reflected RF wave on the waveguide and derives the value of the optimal inductances of the shunt reactors pending in the laser channel to give the smallest RF voltage variation along the transmission line. A sealed-off waveguide $CO_2$ laser with a length of 30 cm and a cross-sectional area of 2mm square was designed and constructed with brass electrodes and beryllia dielectric walls. The laser is transversely excited by radio frequency between 60 and 120 MHz. The output characteristics of the laser is investigated by performing the variation of the total gas pressure, RF input power, and the mixing ratios of the gases. The RF characteristics of the laser channel were measured by a RF probe coupled with a standing wave ratio (SWR) meter and a network analyzer system. With pertinent inductors at the ends of the channel the optical output power produces 40 % more power than that without them. Also the waveguide channel conductances of both the cold and hot states were estimated by the computer analysis of the measured RF reflection coefficients. The estimated shunt resistances of 2,000 Ω and 700 Ω for cold and hot states, each other, make the best computer response to the measured reflection curve. Maximum output power of 3.5 watts is measured under the conditions of the gas mixture of 3:1:1 of He:$CO_2$:$N_2$, the total gas pressure of 50 Torr, input RF power of 200 W. The total reflecting mirror has 1 inch diameter, 2 m radius, and enhanced dielectric coating on the silver layer on the silicon substrate of 0.120 inch (3 mm) thickness, which gives more than 99.5 % reflectivity at 10.6 μm. The partial mirror has the same geometric dimensions, but has 95.7 % reflectivity at the resonator side and antireflection coating on the flat ZnSe substrate at the output side. It is expected to give more optical output power by the optimal mirror reflectance and also by th addition of small amount of xenon gas.

서지기타정보

서지기타정보
청구기호 {DEE 9022
형태사항 1책(면수복잡) : 삽도 ; 26 cm
언어 한국어
일반주기 저자명의 영문표기 : Yoon-Myung Kim
지도교수의 한글표기 : 나정웅
지도교수의 영문표기 : Jung-Woong Ra
학위논문 학위논문(박사) - 한국과학기술원 : 전기 및 전자공학과,
서지주기 참고문헌 수록
주제 Optical wave guides.
Optical pumping.
Radio frequency oscillators.
탄산 가스 레이저. --과학기술용어시소러스
도파관. --과학기술용어시소러스
레이저 여기. --과학기술용어시소러스
고주파 가열. --과학기술용어시소러스
Carbon dioxide lasers.
QR CODE qr code