Time-variant 1D photonic crystals using flowing microdroplets

Chen, Zefeng; Yong, Zheng; Leung, Chi Wah; Zhang, Xuming; Chen, Yihang; Chan, Helen Lai Wa; Wang, Yu

doi:10.1364/oe.20.024330

Cited by 4 publications

(4 citation statements)

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“…Such a structure can be realized in microfluidic system, using microdroplet formation techniques such as flow-focusing or T-junction methodsthe droplets thus formed are inherently periodic and monodispersedas discussed in Ref. [19]. However, in consideration of calculation costs, we resorted to the more general and idealized 1D layered structure ( Fig.…”

Section: Principles and Modellingmentioning

confidence: 99%

“…However, realization of PC modulator is still limited -one approach is to tune the property of constituent material by electric or thermal means [16][17][18], which are essentially conventional modulators. Recently, we proposed a droplet-based time-variant photonic crystal (TvPC) [19] fabricated in microfluidic systems. The structure exhibits a "flowing" property and hence can introduce additional time-domain freedom of optical tuning.…”

Section: Introductionmentioning

confidence: 99%

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Temporal Modulation of Light Intensity via 1d Time-Variant Photonic Crystal Structure

Yong

Chen

et al. 2013

PIER

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Abstract-In this work, we show that light intensity modulation can be realized in the system of one-dimensional time-variant photonic crystals. Different from conventional light modulators, the functioning of the proposed structure emphasizes on its spatial/temporal structures instead of inherent material properties. Additionally, our system can perform inherent light modulation without introducing external stimuli, thus avoiding direct contacts with electrodes (or other modulation sources), which would be preferable in certain environments. The influences of parameters such as light frequency, structure dimensions, and refractive index contrasts on the modulation performance of the time-variant photonic crystal were investigated by numerical simulations. The results provide a new strategy for light modulation, which may add functionalities in optical communication, integrated-optics or display technologies.

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Section: Principles and Modellingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Temporal Modulation of Light Intensity via 1d Time-Variant Photonic Crystal Structure

Yong

Chen

et al. 2013

PIER

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“…23 The ability to control the dynamic properties by tuning the flow characteristics opens interesting perspectives regarding dynamically programmable metamaterials which could be produced by modulating the refractive index of droplet crystals. [24][25][26] Here we investigate collective modes in dense microfluidic crystals under confinement both experimentally and by computer simulations. We show that distinct oscillatory behaviour can be systematically excited by varying the initial conditions through the introduction of specific 'defect' patterns.…”

Section: Introductionmentioning

confidence: 99%

Collective waves in dense and confined microfluidic droplet arrays

et al. 2015

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Excitation mechanisms for collective waves in confined dense one-dimensional microfluidic droplet arrays are investigated by experiments and computer simulations. We demonstrate that distinct modes can be excited by creating specific 'defect' patterns in flowing droplet trains. Excited longitudinal modes exhibit a short-lived cascade of pairs of laterally displacing droplets. Transversely excited modes obey the dispersion relation of microfluidic phonons and induce a coupling between longitudinal and transverse modes, whose origin is the hydrodynamic interaction of the droplets with the confining walls. Moreover, we investigate the long-time behaviour of the oscillations and discuss possible mechanisms for the onset of instabilities. Our findings demonstrate that the collective dynamics of microfluidic droplet ensembles can be studied particularly well in dense and confined systems. Experimentally, the ability to control microfluidic droplets may allow the modulation of the refractive index of optofluidic crystals, which is a promising approach for the production of dynamically programmable metamaterials.

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“…In these micro-systems, optical filters, such as microstructured, 6,18 or dye-doped films 3,19,20 need to be integrated with the microfluidic network to enable compact and portable systems capable of multiplexed detection and analysis. In the vast majority of these reports however, and apart from a few exceptions based on gratings 21 or multiphase flows, 22 the color filters are not tunable, which substantially hinders their ability to perform spectroscopy on-chip.…”

Section: Introductionmentioning

confidence: 99%

Optofluidic-tunable color filters and spectroscopy based on liquid-crystal microflows

2013

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The integration of color filters with microfluidics has attracted substantial attention in recent years, for on-chip absorption, fluorescence, or Raman analysis. We describe such tunable filters based on the micro-flow of liquid crystals. The filter operation is based on the wavelength-dependent liquid crystal birefringence that can be tuned by modifying the flow velocity field in the microchannel. The latter is possible both temporally and spatially by varying the inlet pressure and the channel geometry, respectively. We explored the use of these optofluidic filters for on-chip absorption spectroscopy in poly(dimethylsiloxane) microfluidic systems; by integrating the distance-dependent color filter with a dye-filled micro-channel, the absorption spectrum of a dye could be measured. Liquid crystal microflows substantially simplify the optofluidic integration, actuation and tuning of color filters for lab-on-a-chip spectroscopic applications.

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Time-variant 1D photonic crystals using flowing microdroplets

Cited by 4 publications

References 50 publications

Temporal Modulation of Light Intensity via 1d Time-Variant Photonic Crystal Structure

Temporal Modulation of Light Intensity via 1d Time-Variant Photonic Crystal Structure

Collective waves in dense and confined microfluidic droplet arrays

Optofluidic-tunable color filters and spectroscopy based on liquid-crystal microflows

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