Ding, L., Luo, X., Cheng, L., Thway, M., Song, J. F., Chua, S. J., Chia, E. E. M., Teng, J. H., Advanced Optical Materials 2018, 6, 1800928. https://doi.org/10.1002/adom.201800928
Researches in metamaterials and metasurfaces have signiﬁcant impact on development of terahertz optics and progression of terahertz science and technologies. Further advancement of terahertz systems demands efﬁcient and versatile tunable and reconﬁgurable metadevices for manipulating various properties of terahertz radiation. Here an electrically and thermally tunable silicon metasurface for broadband terahertz antireﬂection applica-tion is demonstrated. The silicon metasurface is composed by interdigitated p–n junctions fabricated using a completely complementary metal-oxide-sem-iconductor (CMOS) compatible process in a silicon photonics foundry. It is atomically smooth without any physically etched pattern nor metal antennas. By supplying bias voltage to the p–n junctions, the complex reﬂection coefﬁcient of the silicon metasurface is continuously tuned between nega-tive and positive values. Complete antireﬂection condition can be precisely achieved, represented by the vanishing of the echo pulse in terahertz time-domain spectroscopy (THz-TDS). The transmission amplitude is bias-polarity dependent, while the phase is simultaneously manipulated. The active silicon metasurface has a unique property that it thermally tunes the reﬂection and electrically tunes transmission. The methodology suggests a new design con-cept using all-silicon platform for making atomically smooth and electrically controlled metadevices in terahertz and other frequency ranges.
The work was ﬁnancially supported by the Institute of Materials Research and Engineering and the Agency for Science, Technology and Research (A*STAR) under Grant Nos. 152 70 00014 and 152 70 00016, as well as Singapore Ministry of Education AcRF Tier 2 Grant (MOE2015-T2-2-065).
This is the peer reviewed version of the following article: Ding, L., Luo, X., Cheng, L., Thway, M., Song, J. F., Chua, S. J., Chia, E. E. M., Teng, J. H., Advanced Optical Materials 2018, 6, 1800928. https://doi.org/10.1002/adom.201800928, which has been published in final form at https://doi.org/10.1002/adom.201800928. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.