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Fabio J. W. A. Martins^a,*, Clauson Carvalho da Silva^b, Christian Lessig^b, Katharina Zähringe^a
Journal of Advanced Optics and Photonics, Vol.1, No.2, pp. 71-94, 2018, DOI:10.32604/jaop.2018.03870
Abstract Packed beds are employed in a wide range of industrial processes, making their optimization an important objective. This requires a thorough understanding of the flow characteristics in the interstices of the bed and the influence of parameters such as packing material, fluid type and flow rate. Next to numerical simulations that have been performed, liquid flows in packed beds have been experimentally investigated by Particle Image Velocimetry (PIV), with optical accessibility obtained using refractive index matching and transparent geometries. For gaseous flows through packed beds, where refractive index matching is not available, there is, in contrast, still a lack of… More >

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Jinsheng Liao^a,*, Liyun Kong^a, Qi Wang^a, Jinqiong Li^a, Guanhuai Peng^a
Journal of Advanced Optics and Photonics, Vol.1, No.2, pp. 95-108, 2018, DOI:10.32604/jaop.2018.02756
Abstract Gd2Sn2O7:Yb3+/Er3+ (abbreviation for GSO: Yb3+/Er3+) nanophosphors codoped with Er3+ (0.1-2 at%) and Yb3+ (0.5-5 at%) were synthesized by a microwave hydrothermal process and annealed at 800 ℃ for 5 h. Powder X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy and upconversion emission spectra were used to characterize the as-synthesized sample. Under the irradiation of 980 nm laser diode, the GSO: Yb3+/Er3+ nanophosphors emitted green emissions centered at 525 and 546 nm (Er3+ :2H11/2→4I15/2 and 4S3/2→4I15/2 transition), red emissions centered at 659 and 677 nm (Er3+:4F9/2→4I15/2 transition). The temperature dependent emission intensity ratio of the thermally coupled levels (2H11/2/4S3/2)… More >

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Suyash Y. Mullemwar ^a, Gajanan D. Zade^b, N. Thejo Kalyani^c,*, Sanjay J. Dhoble^a
Journal of Advanced Optics and Photonics, Vol.1, No.2, pp. 109-124, 2018, DOI:10.32604/jaop.2018.02535
Abstract A novel 2-([1, 1’-biphenyl]-4-yl)-6-chloro-4-phenylquinoline (P-Acetylbiphenyl-Cl-DPQ) phosphor was synthesized by Friedlander condensation reaction at 1400C. To check its suitability for fabricating near UV – organic light emitting diodes (UV-OLEDs) by vacuum vapor deposition, the synthesized organic phosphor is assessed by various characterization techniques such as Fourier Transform Infrared (FTIR) spectroscopy, H-NMR, C-NMR, Thermo gravimetric/ Differential Thermal Analysis (TGA/DTA), optical absorption spectra and photoluminescence (PL) spectra in solid state. The synthesized phosphor is molecularly doped in Polystyrene matrix different wt% to explore its compatibility with polymers. FTIR and NMR confirm the structural formation of the desired complex. TGA and DTA reveal appreciable… More >

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Animesh Bala^a, Kanan Roy Chowdhury^b,*, Md Borhan Mia^a, Mohammad Faisal^a
Journal of Advanced Optics and Photonics, Vol.1, No.2, pp. 125-142, 2018, DOI:10.32604/jaop.2018.03875
Abstract A hexagonal slotted porous core tube lattice cladding photonic crystal fiber (SPC-TLC-PCF) is suggested to simultaneously achieve a very high birefringence and low transmission loss. At the operating frequency of 1 THz the proposed SPC-TLC-PCF yields a birefringence of 9.06×10−2 and effective material loss of 0.047 cm−1. The fiber operates at fundamental mode only and exhibits a small positive dispersion less than 1.6 ps/THz/cm over a band of 250 GHz (0.85 THz to 1.1 THz). Moreover, bending loss is around 1.61×10−7 cm−1 at 1 THz and confinement loss is also pretty small. These favorable attributes endorse this SPC-TLC-PCF much useful… More >

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Henk F.Arnoldus^a,*, Zhangjin Xu^a
Journal of Advanced Optics and Photonics, Vol.1, No.2, pp. 143-155, 2018, DOI:10.32604/jaop.2018.03858
Abstract An oscillating electric dipole in free space emits its energy along straight lines. When the dipole is located in between parallel mirrors, this mechanism is significantly altered. Interference between the electric field of the dipole and the reflected magnetic field by the mirrors leads to a four-vortex structure in the emission pattern. The strength of the vortices depends on the separation between the mirrors and the distance of the dipole to one of the mirrors through a universal function. More >

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