Anomalous change of Airy disk with changing size of spherical particles

Pan, Linchao; Zhang, Fugen; Meng, Rui; Xu, Jie; Zuo, Chenze; Ge, Baozhen

doi:10.1016/j.jqsrt.2015.10.018

Cited by 6 publications

(3 citation statements)

References 9 publications

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“…The physical foundation of the instrument used is the Mie theory, which is based on Maxwell’s equations. The Mie theory is a rigorous solution for the light scattered by a spherical, homogeneous, isotropic, and non-magnetic particle in a non-absorbing medium [ 41 ]. If the particle size is much larger than the wavelength of light, the Fraunhofer diffraction theory can also give a good description of the light scattered in the near-forward directions.…”

Section: Resultsmentioning

confidence: 99%

Real-Time Packing Behavior of Core-Shell Silica@Poly(N-isopropylacrylamide) Microspheres as Photonic Crystals for Visualizing in Thermal Sensing

Manivannan

Huang

et al. 2016

Polymers

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Abstract:We grafted thermo-responsive poly(N-isopropylacrylamide) (PNIPAM) brushes from monodisperse SiO 2 microspheres through surface-initiated atom transfer radical polymerization (SI ATRP) to generate core-shell structured SiO 2 @PNIPAM microspheres (SPMs). Regular-sized SPMs dispersed in aqueous solution and packed as photonic crystals (PCs) in dry state. Because of the microscale of the SPMs, the packing behavior of the PCs in water can be observed by optical microscopy. By increasing the temperature above the lower critical solution temperature (LCST) of PNIPAM, the reversible swelling and shrinking of the PNIPAM shell resulted in dispersion and precipitation (three-dimensional aggregation) of the SPM in aqueous solution. The SPMs were microdispersed in a water layer to accommodate the aggregation along two dimensions. In the microdispersion, the SPMs are packed as PCs with microscale spacing between SPMs below the LCST. When the temperature is increased above the LCST, the microdispersed PCs exhibited a close-packed arrangement along two dimensions with decreased spacing between SPMs. The change in spacing with increasing temperature above the LCST resulted in a color change from red to blue, which could be observed by the naked eye at an incident angle. Thus, the SPM array could be applied as a visual temperature sensor.

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Section: Resultsmentioning

confidence: 99%

Real-Time Packing Behavior of Core-Shell Silica@Poly(N-isopropylacrylamide) Microspheres as Photonic Crystals for Visualizing in Thermal Sensing

Manivannan

Huang

et al. 2016

Polymers

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“…The scattering and absorption of fire smoke can be described by Mie theory, where the particles are considered as sphere or optical equivalent sphere [8,9]. According to Mie theory, the intensity of scattering light depends on the wavelength of the incident light, the observing angle of the scattering light with respect to the direction of incident light, the refractive index and the particle size distribution [10][11][12][13]. The refractive indices of white smoke and black smoke are 1.55 + 0.02i and 1.55 + 0.5i respectively in the air [14][15][16].…”

Section: Introductionmentioning

confidence: 99%

An optical fire detector with enhanced response sensitivities for black smoke based on the polarized light scattering

Deng¹,

Zeng²,

Wang³

et al. 2019

Meas. Sci. Technol.

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Optical fire smoke detectors trigger the fire alarms when the scattering light intensity exceeds a preset threshold. Current optical detectors usually takes a long time or even fail to trigger a fire alarm for black smoke due to the strong absorption and weak scattering efficiency. A fire smoke sensor with dual polarized channels is proposed to adjust the response sensitivities to both white and black smoke. The white and black smoke can be discriminated by the polarization degree, and thus the response sensitivity can be adjusted by a correction factor. A prototype sensor is set up and tested by monodisperse aerosols with a maximum error of 10.1%. According to the experimental results, the prototype sensor could correctly differentiate white smoke and black smoke based on polarization degree, and the fire alarm for black smoke can be triggered as fast as for white smoke.

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“…Single standard particles, which have definite size values and good monodispersity and sphericity, are usually used in optical particle characterization, such as the analysis of light scattering by small particles and the calibration of optical particle measuring systems [1][2][3][4]. While conventional standard particles are usually clustered and preserved in latex [5], it is difficult to obtain a dispersion of appropriate concentration in which a single particle can easily be captured [6,7].…”

Section: Introductionmentioning

confidence: 99%

Generating high-quality single droplets for optical particle characterization with an easy setup

Meng

2018

Meas. Sci. Technol.

Self Cite

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The high-performance and micro-sized single droplet is significant for optical particle characterization. We develop a single-droplet generator (SDG) based on a piezoelectric inkjet technique with advantages of low cost and easy setup. By optimizing the pulse parameters, we achieve various size single droplets. Further investigations reveal that SDG generates single droplets of high quality, demonstrating good sphericity, monodispersity and a stable length of several millimeters.

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Anomalous change of Airy disk with changing size of spherical particles

Cited by 6 publications

References 9 publications

Real-Time Packing Behavior of Core-Shell Silica@Poly(N-isopropylacrylamide) Microspheres as Photonic Crystals for Visualizing in Thermal Sensing

Real-Time Packing Behavior of Core-Shell Silica@Poly(N-isopropylacrylamide) Microspheres as Photonic Crystals for Visualizing in Thermal Sensing

An optical fire detector with enhanced response sensitivities for black smoke based on the polarized light scattering

Generating high-quality single droplets for optical particle characterization with an easy setup

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