Light-driven tunable dual-band plasmonic absorber using liquid-crystal-coated asymmetric nanodisk array

Abstract

We experimentally demonstrated a light-driven reconfigurable near perfect plasmonic absorber working at dual frequencies in infrared range. By employing nanodisks with different sizes in certain arrangement, near perfect absorption of incident electromagnetic waves can be achieved for different working frequencies due to the resonance between the incident light and the nanodisk of different sizes. We showed that optically induced changes in the dielectric constant of the adjacent liquid crystal layer is an effective means to tune the absorption bands of an asymmetric gold nanodisk array. Our liquid crystal based infrared plasmonic absorber can be tuned by using visible light in real time. A tunable range of 25 nm has been confirmed by both simulation and experiment.

MULTIPLE TIME SCALES OPTICAL NONLINEARITIES OF LIQUID CRYSTALS FOR OPTICAL-TERAHERTZ-MICROWAVE APPLICATIONS (Invited Review)

“…The only but important caveat to this is that the effective nonlinearity is proportionally smaller for shorter interaction time, c.f. Equation (19), thereby requiring higher laser intensity to mediate the process.…”

“…Figure 13(a) that tends to diminish the overall response of the NLC-infiltrated structures such as inverse opal photonic crystal or micro-ring resonator [7,11]. In complex non-planar structures with numerous tight corners and crevices such as fishnet or splitring metamaterials other sub-wavelength structures and resonators [12][13][14][15][16][17][18][19][20][21][22][23][24][25] non-uniform director axis alignment, c.f. Figure 13(b) in addition to the immobile layer significantly diminish the effective tunable birefringence of the NLC and device performance.…”

“…The fluid nature of NLC's and their compatibility with other widely used materials ranging from semiconductors to polymers and plasmonics (metals) enable easy integration of such 'crystal' into a large assortment of non-planar structures ranging from nm-sized photonics elements [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25] such as inverse opal photonic crystals and plasmonic/metamaterial structures, c.f. Figures 2(c)-(d), to millimeter-or bulkier microwave devices for tunable -delay line, -phase shifter, -wavelength selector and beam steering devices [26][27][28][29][30][31][32][33][34][35][36][37][38][39][40], to name a few.…”

Plasmon resonance optical tuning based on photosensitive composite structures

“…A structure based on gold nanodisk plasmonic crystal controlled by dual frequency liquid crystal was presented in [18,19]. By adding an azo dye to the LC, the concept was extended to all-optical control of a hybrid system composed of photoswitchable gratings and Au identical nanodisk arrays [22], to a plasmonic absorber using a liquid-crystal-coated asymmetric nanodisk array by mixing the liquid crystal with and to an asymmetric nanodisk array [23].…”

“…The variation of the surrounding's dielectric properties is a much more effective method [15], because it allows a real time, continuous, and reversible tuning of the plasmonic resonance. Liquid crystals (LC) have proven to be effective in tuning optical properties of plasmonic devices [17][18][19][20][21][22][23]. A structure based on gold nanodisk plasmonic crystal controlled by dual frequency liquid crystal was presented in [18,19].…”