Paper
18 October 2019 Step-index sapphire fiber and its application in a terahertz near-field microscopy
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Abstract
In this paper, we present the step-index sapphire fiber, applied as a THz probe. The low THz attenuation of sapphire makes it attractive for fabrication of THz optical components. Moreover, it has a high refractive index in THz range, which guarantees a strong modal confinement in a fiber core. The advantages of the edge-defined film-fed growth (EFG) technique allow for fabrication of fibers with close-to-cylindrical shape, the length of 1 m and longer, and the subwavelength diameter of 150 − 400 μm. In order to improve the coupling efficiency, the fiber has polished flat ends. We apply the fabricated 300-μm-diameter sapphire fiber for the THz near-field scanning-probe microscopy. The spatial resolution of our experimental setup is defined by the fiber diameter, thus, it reaches ~ λ/4 for the radiation wavelength λ = 1200 μm. The obtained images of the test objects demonstrate the advanced resolution, which is close to the theoretical limit and beyond the Abbe diffraction limit.
© (2019) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
G. M. Katyba, N. V. Chernomyrdin, I. N. Dolganova, A. A. Pronin, I. V. Minin, O. V. Minin, K. I. Zaytsev, and V. N. Kurlov "Step-index sapphire fiber and its application in a terahertz near-field microscopy", Proc. SPIE 11164, Millimetre Wave and Terahertz Sensors and Technology XII, 111640G (18 October 2019); https://doi.org/10.1117/12.2536305
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Cited by 8 scholarly publications.
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KEYWORDS
Terahertz radiation

Sapphire

Spatial resolution

Crystals

Metals

Microscopy

Near field scanning optical microscopy

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