A number of transverse stratified configurations of metal and dielectric layers are studied for modulating Terahertz radiation in amplitude and phase. Pass band flat-top response and high wide-band transmission is achieved by means of a metallic grating filled with Liquid Crystal (LC) in different configurations and with the use of either grazing angles of incidence or cuts pierced within the grating. The transverse configuration with thin LC films allows for high speed tunability with low applied voltage. A dielectric grating with non-continuous electrodes is studied showing wide pass band response suitable for phase modulation applications.
2. Mendis, R., A. Nag, F. Chen, and D. M. Mittleman, "A tunable universal terahertz filter using artificial dielectrics based on parallel-plate waveguides," Appl. Phys. Lett., Vol. 97, 131106, 2010. doi:10.1063/1.3495994
3. Unlu, M., C. W. Berry, S. Li, S.-H. Yang, M. R. Hashemi, and M. Jarrahi, "Broadband terahertz modulation using reconfigurable mesh filters," 2013 IEEE 14th Annual Wireless and Microwave Technology Conference (WAMICON), 1-3, Apr. 7-9, 2013.
4. Zhu, W. M., H. Cai, T. Mei, T. Bourouina, J. F. Tao, G.-Q. Lo, D.-L. Kwong, and A. Q. Liu, "A MEMS tunable metamaterial filter," 2010 IEEE 23rd International Conference on Micro Electro Mechanical Systems (MEMS), 196-199, Jan. 24-28, 2010.
6. Yang, F. and J. R. Sambles, "Microwave liquid crystal wavelength selector," Appl. Phys. Lett.,, Vol. 79, No. 22, 3717-3719, Nov. 2001. doi:10.1063/1.1419240
7. Medina, F., F. Mesa, and D. C. Skigin, "Extraordinary transmission through arrays of slits: A circuit theory model," IEEE Transactions on Microwave Theory and Techniques, Vol. 58, No. 1, 105-115, Jan. 2010. doi:10.1109/TMTT.2009.2036341
8. Yeh, P. and C. Gu, Optics of Liquid Crystal Displays, 15-47, Wiley Publishers, Hooboken, New Jersey, 2010.
9. Yang, C. S., C. J. Lin, R. P. Pan, C. T. Que, K. Yamamoto, M. Tani, and C. L. Pan, "The complex refractive indices of the liquid crystal mixture E7 in the terahertz frequency range," Journal of the Optical Society of America B, Vol. 27, No. 9, 1866-1873, 2010. doi:10.1364/JOSAB.27.001866
10. De Ceglia, D., M. A. Vincenti, and M. Scalora, "Wideband plasmonic beam steering in metal gratings," Optics Letters, Vol. 37, No. 2, 271-273, 2012. doi:10.1364/OL.37.000271
11. Lo Forti, D., D. de Ceglia, M. A. Vincenti, M. Scalora, and R. G. Lindquist, "Beaming and filtering at terahertz frequencies in liquid crystal filled metallic grating," Proc. SPIE 8828, Liquid Crystals XVII, 88281E, Sep. 12, 2013.
12. Lockyear, M. J., A. P. Hibbins, and J. R. Sambles, "Transmission of microwaves through a stepped subwavelength slit," Appl. Phys. Lett., Vol. 91, No. 25, 251106-1-251106-3, Dec. 2007. doi:10.1063/1.2824458
13. Zhao, Y. and D. Grischkowsky, "A new method for the realization of a tunable terahertz photonic bandgap," Conference on Lasers and Electro-Optics, CLEO 2007, 1-2, May 6-11, 2007.
14. Loewen, E. G. and E. Popov, Diffraction Gratings and Applications, M. Dekker Publisher, New York, 1997.