title: Low temperature and high magnetic field spectroscopic ellipsometry system.
abstract: We report on the design and implementation of a spectral ellipsometer at near-infrared wavelength (700-1000 nm) for samples placed in high magnetic fields (up to 14 T) at low temperatures (~4.2 K). The main optical components are integrated in a probe, which can be inserted into a conventional long-neck He dewar and has a very long free-space optical path (~1.8 m×2). A polarizer-sample-(quarter-wave plate)-rotating analyzer configuration was employed. Two dielectric mirrors, one before and one after the sample in the optical path, helped to reflect the light back to the analyzer and a two-axis piezo-driven goniometer under the sample holder was used to control the direction of the reflected light. Functional test results performed on an intrinsic GaAs wafer and analysis on the random error of the system are shown. We obtained both amplitude and phase ellipsometric spectra simultaneously and observed helicity transformation at energies near the GaAs exciton transitions in the phase spectra. Significant shifts of them induced by magnetic fields were observed and fitted with a simple model. This system will allow us to study the collective magneto-optical response of materials and spatial dispersive exciton-polariton related problems in high external magnetic fields at low temperatures.
authors.affiliation: Department of Electronics Engineering and Institute of Electronics, National Chiao Tung University, 1001 University Road, Hsinchu 300, Taiwan.
authors.forename: Sheng-Kai
authors.initials: SK
authors.lastname: Su
authors.affiliation: Center for Nano Science and Technology, National Chiao Tung University, Hsinchu, Taiwan.
authors.forename: Liang-Chen
authors.initials: LC
authors.lastname: Li
authors.affiliation: Department of Physics, National Chung Hsing University, Taichung, Taiwan.
authors.forename: Yuen-Wuu
authors.initials: YW
authors.lastname: Suen
authors.affiliation: Department of Electronics Engineering and Institute of Electronics, National Chiao Tung University, 1001 University Road, Hsinchu 300, Taiwan.
authors.forename: Jau-Yang
authors.initials: JY
authors.lastname: Wu
authors.affiliation: Department of Physics, National Chung Hsing University, Taichung, Taiwan.
authors.forename: Hong-Rong
authors.initials: HR
authors.lastname: Kuo
authors.affiliation: National Nano Device Laboratories, Hsinchu, Taiwan.
authors.forename: Yu-Tai
authors.initials: YT
authors.lastname: Sung
authors.affiliation: Department of Electronics Engineering and Institute of Electronics, National Chiao Tung University, 1001 University Road, Hsinchu 300, Taiwan.
authors.forename: Chien-Ping
authors.initials: CP
authors.lastname: Lee
authors.affiliation: Department of Electronics Engineering and Institute of Electronics, National Chiao Tung University, 1001 University Road, Hsinchu 300, Taiwan.
authors.forename: Oleksandr
authors.initials: O
authors.lastname: Voskoboynikov