Frequency-addressed tunable transmission in optically thin metallic nanohole arrays with dual-frequency liquid crystals

Hao, Qingzhen; Zhao, Yanhui; Juluri, Bala Krishna; Kiraly, Brian; Liou, J.; Khoo, Iam Choon; Huang, Tony Jun

doi:10.1063/1.3581037

Cited by 26 publications

(21 citation statements)

References 39 publications

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“…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.…”

Section: Multiple Time Scales Nonlinearities Of Nematic Liquid Crystamentioning

confidence: 99%

“…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.…”

Section: F Figures 2(a)-(b)mentioning

confidence: 99%

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

Khoo¹,

Zhao²

2014

PIER

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Abstract-We provide a critical account of the dynamics of laser induced refractive index changing mechanisms in nematic liquid crystals which may be useful for all-optical switching and modulation applications in the visible as well as the Terahertz and long-wavelength regime. In particular, the magnitude and response times of optical Kerr effects associated with director axis reorientation, thermal and order parameter changes, coupled flow-reorientation effects and individual molecular electronic responses are thoroughly investigated and documented, along with exemplary experimental demonstrations. Emphases are placed on identifying parameter sets that will enable all-optical switching with much faster response times compared to their conventional electro-optics counterparts.

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Section: Multiple Time Scales Nonlinearities Of Nematic Liquid Crystamentioning

confidence: 99%

Section: F Figures 2(a)-(b)mentioning

confidence: 99%

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

Khoo¹,

Zhao²

2014

PIER

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“…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].…”

Section: Introductionmentioning

confidence: 99%

“…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]. 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].…”

Section: Introductionmentioning

confidence: 99%

Plasmon resonance optical tuning based on photosensitive composite structures

et al. 2014

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This paper reports a numerical investigation of a periodic metallic structure sandwiched between two quartz plates. The volume comprised between the quartz plates and the metallic structure is infiltrated by a mixture of azo-dye-doped liquid crystal. The exposure to a low power visible light beam modifies the azo dye molecular configuration, thus allowing the wavelength shift of the resonance of the system. The wavelength shift depends on the geometry of the periodic structure and it also depends on the intensity of the visible light beam.

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“…At certain wavelengths, maximum coupling from electromagnetic waves to localized surface plasmons can be achieved and these are known as the localized surface plasmon resonances (LSPRs) of the structure. LSPRs of metal nanostructures depend on properties such as the size, 10,11 shape, 12-14 metal material, 15 surrounding dielectric material, [16][17][18][19][20][21][22] and the charge of the metal. [23][24][25][26][27][28][29][30] Active plasmonic devices can be realized by externally tuning the LSPR of nanostructures.…”

mentioning

confidence: 99%

Shifts in plasmon resonance due to charging of a nanodisk array in argon plasma

Lapsley

Shahravan

Hao

et al. 2012

Applied Physics Letters

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A method for generating charge-induced plasmonic shifts, using argon plasma to charge nanoparticle arrays, is presented. Particles develop a negative charge, due to enhanced collisions with high-temperature electrons, in low-temperature plasmas. The negative charge generated causes a blue shift in the localized surface plasmon resonance. The dynamics of the shift were recorded and discussed. This effect could be used as a real-time method for studying the dynamics for charging in plasma. Plasmonics deals with optically excited, oscillations of electrons at the interface between a metal and a dielectric, 1 and this phenomenon has driven the development of many optical devices. 2-9 Surface plasmons excited in metal structures, confined at the nanoscale in three dimensions (i.e., nanoparticles, nanodisks, etc.), are known as localized surface plasmons. At certain wavelengths, maximum coupling from electromagnetic waves to localized surface plasmons can be achieved and these are known as the localized surface plasmon resonances (LSPRs) of the structure. LSPRs of metal nanostructures depend on properties such as the size, 10,11 shape, 12-14 metal material, 15 surrounding dielectric material, [16][17][18][19][20][21][22] and the charge of the metal. [23][24][25][26][27][28][29][30] Active plasmonic devices can be realized by externally tuning the LSPR of nanostructures. Previously, chemical/electrochemical charging was used to actively tune the LSPR of arrays of both silver 24,25,30 and gold 23,26,27,29 nanostructures; however, this process is relatively slow. In this study, a rapid shift in the LSPR of an array of gold nanodisks was induced by surrounding the particles with a low-temperature argon plasma. This shift can be explained by the charging effect of the plasma. [31][32][33][34] Charging by the plasma takes place in only seconds, where chemical/electrochemical charging can take several minutes 24 to hours. 27 This method allows real-time monitoring of the charging effect induced by low-pressure plasmas and could be utilized for photonics applications based on the LSPR shift.In the experiment, the optical extinction spectrum of an array of gold nanodisks was measured while generating plasma. An array of gold nanodisks (diameters of 120 nm, thicknesses of 30 nm, and a periodicity of 300 nm) was fabricated on glass via electron-beam lithography. 35 A custom vacuum chamber was designed to include two flat, parallel windows to allow transmission of a probe light (Fig. 1(a)). The nanodisk array was placed inside the vacuum chamber where it was attached to one of the flat windows. The probe light, ejected from the input optical fiber and collimated by a lens, traveled through the vacuum chamber and the sample. The output light was collected by the output lens/optical fiber and delivered to an optical spectrometer. A vacuum system was used to evacuate the chamber to a base pressure of 150 mTorr. Argon was introduced into the chamber using a mass flow controller. The argon gas was introduced at a flow rate of 6 SCCM ...

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Frequency-addressed tunable transmission in optically thin metallic nanohole arrays with dual-frequency liquid crystals

Cited by 26 publications

References 39 publications

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

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

Plasmon resonance optical tuning based on photosensitive composite structures

Shifts in plasmon resonance due to charging of a nanodisk array in argon plasma

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