Current Optics and Photonics
Vol. 6, No.2(Apr. 2022)
한국광학회지
Vol. 33, No.2(Apr. 2022)
K-Light
Vol5, No.2(Apr. 2022)
한국광학회 공식 SNS 계정 바로가기
트위터
인스타그램
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[Editors Pick] Current Optics and Photonics Vol. 6 no. 2 (2022 April)
Highly Birefringent Slotted-porous-core Photonic Crystal Fiber with Elliptical-hole Cladding for Terahertz Applications
Yong Soo Lee1, Soeun Kim2 *, and Kyunghwan Oh1 **
Current Optics and Photonics Vol. 6 No.2 (2022 April) pp. 129-136
DOI: https://doi.org/10.3807/COPP.2022.6.2.129
Fig. 1 Transverse cross section of the proposed photonic crystal fiber (PCF) design, and the extended view of the slotted porous core.
Keywords: High birefringence, Photonic crystal fiber, Terahertz
OCIS codes: (060.2280) Fiber design and fabrication; (060.5295) Photonic crystal fibers; (260.1440) Birefringence
Abstract
We propose a photonic crystal fiber (PCF) with a slotted porous core and elliptical-hole cladding, for high birefringence in the terahertz regime. Asymmetry in the guided mode is obtained mainly by using arrays of elliptical air holes in the TOPAS® polymer cladding. We investigate the tradeoff between several structural parameters and find optimized values that can have a high birefringence while satisfying the single-mode condition. The optical properties in the terahertz regime are thoroughly analyzed in numerical simulations, using a full-vector finite-element method with the perfectly-matched-layer condition. In an optimal design, the proposed photonic crystal fiber shows a high birefringence of 8.80 × 10−2 and an effective material loss of 0.07 cm−1> at a frequency of 1 THz, satisfying the single-mode-guidance condition at the same time. The proposed PCF would be useful for various polarization-management applications in the terahertz range.
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[하이라이트 논문] 한국광학회지 Vol. 33 No.2 (2022 April)
불완전한 보정기를 적용한 자유형 뮬러행렬타원계의 설계
Design of a Free-form Mueller Matrix Ellipsometer with Imperfect Compensators
김상열†
한국광학회지 Vol. 33 No.2 (2022 April) pp. 59-66
DOI: https://doi.org/10.3807/KJOP.2022.33.2.059
Fig. 1 Generation of an elliptically polarized light.
Keywords: 불완전한 보정기, 뮬러행렬타원계, 광파장대역
OCIS codes: (000.2170) Equipment and techniques; (120.2130) Ellipsometry and polarimetry; (120.5050) Phase measurement
초록
각 편광소자의 방위각을 자유롭게 제어하는 자유형 구동방식에 기반한 뮬러행렬타원계(Mueller matrix ellipsometer, MME)를 제시한다. 보정기의 위상지연각 분산특성과 전기장 투과율비의 파장의존성을 고려하여 시료에 입사하는 빛의 편광상태를 최적화하기 위한 편광자의 방위각과 편광자측 보정기의 방위각 조합들을 제시한다. 시료로부터 출사하는 빛의 스톡스상수들을 빠르고 정확하게 측정할 수 있는 검광자의 방위각과 검광자측 보정기의 방위각 조합들, 그리고 출사하는 빛의 스톡스상수들을 구하는 수학적 표현들을 제시한다. 이 MME는 이상적이지 않은 4분파장 위상지연자를 적용할 수 있도록 보정기 선택의 폭을 넓혀주므로 깊은 자외선(deep ultraviolet)부터 근적외선(near infrared)에 이르는 매우 넓은 파장 대역에 걸쳐 작동하는 뮬러행렬 분광타원계(Mueller matrix spectroscopic ellipsometer, MMSE)의 제작과 활용을 용이하게 해 줄 것이다.
Abstract
A free-form Mueller matrix ellipsometer (MME) based on independent control of the azimuthal angle of each polarizing element is introduced. The azimuthal angles of the polarizer and the matching compensator which generate the optimum Stokes vectors of an incident beam are investigated for the polarization state generator, where the spectral responses of the retardation angle and transmittance ratio of a nonideal compensator are taken into account. Similarly, the azimuthal angles of the analyzer and the corresponding compensator are investigated for the polarization-state detector, to unambiguously determine the Stokes vector of the outcoming beam from the sample, and explicit expressions for the Stokes elements are derived. Since the suggested technique enables one to utilize a nonideal quarter-wave plate as the compensator for an MME, it will contribute to the construction and application of a Mueller matrix spectroscopic ellipsometer (MMSE) operating over a wide spectral range from deep ultra-violet to near infrared.
