서지주요정보
표면 감쇠파를 결합한 미소 공진구의 품위값 측정 = Direct measurement of microsphere cavity quality factors via evanescent-wave coupling
서명 / 저자 표면 감쇠파를 결합한 미소 공진구의 품위값 측정 = Direct measurement of microsphere cavity quality factors via evanescent-wave coupling / 김선경.
저자명 김선경 ; Kim, Sun-Kyung
발행사항 [대전 : 한국과학기술원, 2002].
Online Access 원문보기 원문인쇄

소장정보

등록번호

8012643

소장위치/청구기호

학술문화관(문화관) 보존서고

MPH 02003

휴대폰 전송

도서상태

이용가능

대출가능

반납예정일

초록정보

High-Q microspheres have attracted much attention as a useful and practical tool in various branches of optical science, particularly in laser frequency stabilization, selective optical filters, and a microcavity for lasers with quantum radiators such as quantum dots and single atoms. In this experiment, a prism-microsphere evanescent-wave-coupling configuration was used to measure the WGM cavity quality factors of homemade microspheres. An extended cavity diode laser (New Focus, Vortex 6000) of 780nm was used as a probe beam. The probe beam was focused under an optimal angle at the inner surface of a coupling prism. The microsphere fabricated by melting the end of an optical fiber was hold in a fiber chuck holder and positioned its equator next to the focal spot of the probe beam on the prisms surface. For an efficient coupling, the distance between the prism and the sphere was controlled in a step of about 0.1㎛ by a PZT positioner (Thorlabs, PE4). The WGM Q factors were measured from the reflectance spectrum obtained by scanning the wavelength of a probe laser. Cavity quality factors up to $4\times10^8$ corresponding to a linewidth of 1-2MHz, have been measured. This linewidth was mainly limited by the linewidth of the probe laser, limiting the highest Q value measurable in our experiment to be about $4\times10^8$. We also observed equally spaced WGM modes with about 2GHz spacing, which arises from the frequency splitting of different Z components of angular momentum due to slight eccentricity in microsphere. We also observed the dependence of coupling linewidth and amplidute of resonant dips on the distance between the prism and the microsphere. At about 0.5㎛, the amplitude of resonant dip was maximized, which was up to about 20% of off-resonance signal amplitude. As the distance decreased to a value less than 0.5㎛, the resonance transmission diminished. At this critical gap distance, the measured factor becomes a factor of 2 smaller than the intrinsic quality factor. As the distance decreased below $d_{crit}$, the linewidth of the modes were broadened exponentially as a function of the resonant-dip amplitude.

서지기타정보

서지기타정보
청구기호 {MPH 02003
형태사항 [iii], 45 p. : 삽도 ; 26 cm
언어 한국어
일반주기 저자명의 영문표기 : Sun-Kyung Kim
지도교수의 한글표기 : 안경원
지도교수의 영문표기 : Kyung-Won An
학위논문 학위논문(석사) - 한국과학기술원 : 물리학과,
서지주기 참고문헌 : p. 43-45
주제 미소 공진구
품위값
표면 감쇠파
공진기
결합
microsphere
quality factor
evanescent field
cavity
coupling
QR CODE qr code