Estimation of refractive index of eggshell in intact egg using terahertz time-domain spectroscopy

Khaliduzzaman, Alin, Keiichiro Shiraga, Naoshi Kondo, and Yuichi Ogawa. “Estimation of refractive index of eggshell in intact egg using terahertz time-domain spectroscopy.” In Fourth International Seminar on Photonics, Optics, and Its Applications (ISPhOA 2020), vol. 11789, p. 117890F. International Society for Optics and Photonics, 2021.

Abstract

Terahertz is a relatively new, and yet to be explored that how it interacts with many biological objects like avian eggshell. Eggshell protects internal contents of egg from contaminants and ultraviolet radiation. It also acts as a major mineral source for embryonic development. The refractive index indicating eggshell compactness could be a potential quality criterion of shell for both table and hatching egg. But a little is known about refractive index of eggshell. However, the available information is only based on destructive method which is not suitable to use in many cases due to loss of eggshell integrity. Therefore, we aim to develop a non-destructive protocol of eggshell refractive index measurement using terahertz time domain spectroscopy (THz-TDS) which can directly derive refractive index in the terahertz region from the temporal pulses. In order to get rid of intense terahertz absorption by egg albumen, we used THz-TDS to measure reflectance of intact eggshell in the 0.2-1.2 THz.

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