We fabricated sub-wavelength patterned gold plasmonic nanostructures on a quartz substrate through the focused ion beam (FIB) technique. The perforated gold film demonstrated optical transmission peaks in the visible range, which therefore can be used as a plasmonic color filter. Furthermore, by integrating a layer of photoresponsive liquid crystals (LCs) with the gold nanostructure to form a hybrid system, we observed a red-shift of transmission peak wavelength. More importantly, the peak intensity can be further enhanced more than 10% in transmittance due to the refractive index match of the media on both sides of it. By optically pumping the hybrid system using a UV light, nematic−isotropic phase transition of the LCs was achieved, thus changing the effective refractive index experienced by the impinging light. Due to the refractive index change, the transmission peak intensity was modulated accordingly. As a result, an optically tunable plasmonic color filter was achieved. This kind of color filters could be potentially applied to many applications, such as complementary metal-oxide-semiconductor (CMOS) image sensors, liquid crystal display devices, light emitting diodes, etc.
Hybrid System Azobenzene Effective Refractive Index BMAB Plasmonic Nanostructures
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.
This is a preview of subscription content, log in to check access.
This work was financially supported by Agency for Science, Technology, and Research (A*STAR), under the Grant Nos. 0921540099 and 0921540098.
H. Raether, Surface Plasmons on Smooth and Tough Surfaces and on Gratings (Springer, Berlin, 1988)
E. Ozbay, Plasmonics: merging photonics and electronics at nanoscale dimensions. Science 311, 189–193 (2006)
Y.J. Liu, Q.Z. Hao, J.S.T. Smalley, J. Liou, I.C. Khoo, T.J. Huang, A frequency-addressed plasmonic switch based on dual-frequency liquid crystals. Appl. Phys. Lett. 97, 091101 (2010)
Y.J. Liu, Y.B. Zheng, J. Liou, I.-K. Chiang, I.C. Khoo, T.J. Huang, All-optical modulation of localized surface plasmon coupling in a hybrid system composed of photo-switchable gratings and Au nanodisk arrays. J. Phys. Chem. C 115, 7717–7722 (2011)
G.T. Boyd, Z.H. Yu, Y.R. Shen, Photoinduced luminescence from the noble metals and its enhancement on roughened surfaces. Phys. Rev. B 33, 7923–7936 (1986)
M. Xiao, N. Rakov, Surface propagation with a large spectral red-shift on a gold thin film containing subwavelength holes. Phys. Lett. A 309, 452–456 (2003)
Y.J. Liu, E.S.P. Leong, B. Wang, J.H. Teng, Optical transmission enhancement and tuning by overlaying liquid crystals on a gold film with patterned nanoholes. Plasmonics 6, 659–664 (2011)
M. Takei, H. Yui, Y. Hirose, T. Sawada, Femtosecond time-resolved spectroscopy of photoisomerization of methyl orange in cyclodextrincs. J. Phys. Chem. A 105, 11395–11399 (2001)
I.C. Khoo, J.-H. Park, J.D. Liou, Theory and experimental studies of all-optical transmission switching in a twist-alignment dye-doped nematic liquid crystal. J. Opt. Soc. Am. B 25, 1931–1937 (2008)