Byeongho Park1,†, Yeon Kyung Cha2,†, Jisung Kwak1, Kyeong Seob Hwang1,3, Hyo-Suk Kim1, Subeen Park1, Yusin Pak1, Tai Hyun Park2,4*, Hyun Seok Song1,5*, Jae Hun Kim1,*
1Korea Institute of Science and Technology (KIST), Seongbuk-gu, Seoul 02792, Republic of Korea
2Interdisciplinary Program in Bioengineering, Seoul National University, Gwanak-gu, Seoul 08826, Republic of Korea
3School of Mechanical Engineering, Yonsei University, Seoul 03722, Republic of Korea
4School of Chemical and Biological Engineering, and Institute of Chemical Processes, Seoul National University, Gwanak-gu, Seoul 08826, Republic of Korea
5Division of Bio-Medical Science & Technology, KIST School, Korea University of Science and Technology (UST), Seoul 02792, Republic of Korea
†B.P. and Y.K.C. contributed equally.
A photoreceptor on the retina acts as an optical waveguide to transfer an individual photonic signal to the cell inside, which is determined by the refractive index of internal materials. Under the photoactivation of photoreceptors making conformational and chemical variation in a visual cell, the optical signal modulation is demonstrated using an artificial photoreceptor-based waveguide with a controlling beam refraction. Two types of nanodiscs are made of human photoreceptor proteins, short-wavelength-sensitive opsin and rhodopsin, with spectral sensitivity. The refractive index and nonlinear features of those two photosensitive nanodiscs are investigated as fundamental properties. The photonanodiscs are photoactivated in such a way that allow refractive index tuning over 0.18 according to the biological function of the respective proteins with color-dependent response.