scholarly journals Polymer-Based Microring Resonator with the Multimode Interference Coupler Operating at Very-Near-Infrared Wavelengths

2019 ◽  
Vol 9 (13) ◽  
pp. 2715 ◽  
Author(s):  
Huanlin Lv ◽  
Yuxin Liang ◽  
Zhenlin Wu ◽  
Xiuyou Han ◽  
Geert Morthier ◽  
...  
Keyword(s):  
Near Infrared ◽  
High Potential ◽  
Microring Resonator ◽  
Multimode Interference ◽  
Q Factor ◽  
Fluorinated Polymer ◽  
Sensing Applications ◽  
Soft Mold ◽  
Multimode Interference Coupler ◽  
Infrared Wavelengths

A microring resonator with the multimode interference coupler is fabricated on the polymer platform by using UV-based soft nanoimprint technique. A unique class of fluorinated polymer, perfluoropolyether (PFPE), is employed for the fabrication of the flexible soft mold. By optimizing the proportion between Ormocore and the thinner maT, the microring resonator is fabricated almost without residual layer. The fabricated device with a Q-factor up to 2.3 × 104 is demonstrated for very-near-infrared wavelengths, which shows high potential for sensing applications.

scholarly journals A broadband 2×2 multimode interference coupler for mid-infrared wavelengths

2021 ◽  
Author(s):  
Callum Stirling ◽  
Robert Halir ◽  
Alejandro Sánchez-Postigo ◽  
Zhibo Qu ◽  
Jamie Reynolds ◽  
...  
Keyword(s):  
Multimode Interference ◽  
Mid Infrared ◽  
Multimode Interference Coupler ◽  
Infrared Wavelengths

scholarly journals Electromechanically reconfigurable optical nano-kirigami

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Shanshan Chen ◽  
Zhiguang Liu ◽  
Huifeng Du ◽  
Chengchun Tang ◽  
Chang-Yin Ji ◽  
...  
Keyword(s):  
Near Infrared ◽  
Large Range ◽  
Three Dimensional ◽  
High Contrast ◽  
Si Substrate ◽  
High Modulation ◽  
Gold Nanostructure ◽  
Infrared Wavelengths ◽  
On Chip ◽  
Nano Electromechanical System

AbstractKirigami, with facile and automated fashion of three-dimensional (3D) transformations, offers an unconventional approach for realizing cutting-edge optical nano-electromechanical systems. Here, we demonstrate an on-chip and electromechanically reconfigurable nano-kirigami with optical functionalities. The nano-electromechanical system is built on an Au/SiO2/Si substrate and operated via attractive electrostatic forces between the top gold nanostructure and bottom silicon substrate. Large-range nano-kirigami like 3D deformations are clearly observed and reversibly engineered, with scalable pitch size down to 0.975 μm. Broadband nonresonant and narrowband resonant optical reconfigurations are achieved at visible and near-infrared wavelengths, respectively, with a high modulation contrast up to 494%. On-chip modulation of optical helicity is further demonstrated in submicron nano-kirigami at near-infrared wavelengths. Such small-size and high-contrast reconfigurable optical nano-kirigami provides advanced methodologies and platforms for versatile on-chip manipulation of light at nanoscale.

scholarly journals High-Q-Factor Tunable Silica-Based Microring Resonators

Photonics ◽  
2021 ◽  
Vol 8 (7) ◽  
pp. 256
Author(s):  
Yue-Xin Yin ◽  
Xiao-Pei Zhang ◽  
Xiao-Jie Yin ◽  
Yue Li ◽  
Xin-Ru Xu ◽  
...  
Keyword(s):  
Optical Communications ◽  
Microring Resonator ◽  
Microring Resonators ◽  
Q Factor ◽  
Notch Depth ◽  
Critical Coupling ◽  
Practical Application ◽  
Coupling Condition ◽  
High Q ◽  
Racetrack Resonator

A high-Q-factor tunable silica-based microring resonator (MRR) is demonstrated. To meet the critical-coupling condition, a Mach–Zehnder interferometer (MZI) as the tunable coupler was integrated with a racetrack resonator. Then, 40 mW electronic power was applied on the microheater on the arm of MZI, and a maximal notch depth of about 13.84 dB and a loaded Q factor of 4.47 × 106 were obtained. The proposed MRR shows great potential in practical application for optical communications and integrated optics.

Spectral characteristics of leafy spurge (Euphorbia esula) leaves and flower bracts

Weed Science ◽  
2004 ◽  
Vol 52 (4) ◽  
pp. 492-497 ◽  
Author(s):  
E. Raymond Hunt ◽  
James E. McMurtrey ◽  
Amy E. Parker Williams ◽  
Lawrence A. Corp
Keyword(s):  
Remote Sensing ◽  
High Performance ◽  
Near Infrared ◽  
Spectral Characteristics ◽  
Leafy Spurge ◽  
Hyperspectral Remote Sensing ◽  
Total Carotenoids ◽  
Physiological Basis ◽  
Infrared Wavelengths ◽  
Pigment Concentrations

Leafy spurge can be detected during flowering with either aerial photography or hyperspectral remote sensing because of the distinctive yellow-green color of the flower bracts. The spectral characteristics of flower bracts and leaves were compared with pigment concentrations to determine the physiological basis of the remote sensing signature. Compared with leaves of leafy spurge, flower bracts had lower reflectance at blue wavelengths (400 to 500 nm), greater reflectance at green, yellow, and orange wavelengths (525 to 650 nm), and approximately equal reflectances at 680 nm (red) and at near-infrared wavelengths (725 to 850 nm). Pigments from leaves and flower bracts were extracted in dimethyl sulfoxide, and the pigment concentrations were determined spectrophotometrically. Carotenoid pigments were identified using high-performance liquid chromatography. Flower bracts had 84% less chlorophylla, 82% less chlorophyllb, and 44% less total carotenoids than leaves, thus absorptance by the flower bracts should be less and the reflectance should be greater at blue and red wavelengths. The carotenoid to chlorophyll ratio of the flower bracts was approximately 1:1, explaining the hue of the flower bracts but not the value of reflectance. The primary carotenoids were lutein, β-carotene, and β-cryptoxanthin in a 3.7:1.5:1 ratio for flower bracts and in a 4.8:1.3:1 ratio for leaves, respectively. There was 10.2 μg g−1fresh weight of colorless phytofluene present in the flower bracts and none in the leaves. The fluorescence spectrum indicated high blue, red, and far-red emission for leaves compared with flower bracts. Fluorescent emissions from leaves may contribute to the higher apparent leaf reflectance in the blue and red wavelength regions. The spectral characteristics of leafy spurge are important for constructing a well-documented spectral library that could be used with hyperspectral remote sensing.

scholarly journals Highly Efficient Near-Infrared Detector Based on Optically Resonant Dielectric Nanodisks

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 428
Author(s):  
Reza Masoudian Saadabad ◽  
Christian Pauly ◽  
Norbert Herschbach ◽  
Dragomir N. Neshev ◽  
Haroldo T. Hattori ◽  
...  
Keyword(s):  
Quantum Efficiency ◽  
High Speed ◽  
Near Infrared ◽  
Infrared Detector ◽  
High Quantum Efficiency ◽  
Fast Detection ◽  
High Quantum ◽  
Resonant Modes ◽  
Infrared Wavelengths ◽  
Dielectric Metasurface

Fast detection of near-infrared (NIR) photons with high responsivity remains a challenge for photodetectors. Germanium (Ge) photodetectors are widely used for near-infrared wavelengths but suffer from a trade-off between the speed of photodetection and quantum efficiency (or responsivity). To realize a high-speed detector with high quantum efficiency, a small-sized photodetector efficiently absorbing light is required. In this paper, we suggest a realization of a dielectric metasurface made of an array of subwavelength germanium PIN photodetectors. Due to the subwavelength size of each pixel, a high-speed photodetector with a bandwidth of 65 GHz has been achieved. At the same time, high quantum efficiency for near-infrared illumination can be obtained by the engineering of optical resonant modes to localize optical energy inside the intrinsic Ge disks. Furthermore, small junction capacitance and the possibility of zero/low bias operation have been shown. Our results show that all-dielectric metasurfaces can improve the performance of photodetectors.

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