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We report a high-responsive hot-electron photodetector based on the integration of an Au–MoS2 junction with a silicon nitride microring resonator (MRR) for detecting telecom-band light. The coupling of the evanescent field of the silicon nitride MRR with the Au–MoS2 Schottky junction region enhances the hot-electron injection efficiency. The device exhibits a high responsivity of 154.6 mA W−1 at the wavelength of 1516 nm, and the moderately uniform responsivities are obtained over the wavelength range of 1500–1630 nm. This MRR-enhanced MoS2 hot-electron photodetector offers possibilities for integrated optoelectronic systems. [ABSTRACT FROM AUTHOR]

Abstract: Optical second harmonic generations (SHGs) from atomically thin MoTe2 flakes with 2H and 1T′ phases are studied. From 2H‐MoTe2 samples with odd (even) numbers of layers, strong (negligible) SHGs are observed due to the layer‐dependent broken inversion symmetry. When pumped by a telecom‐band laser, SHG from a monolayer 2H‐MoTe2 is about one order of magnitude stronger than that from a monolayer WS2; an extremely high second‐order nonlinear susceptibility of 2.5 nm V−1 is estimated, presenting the highest value among those reported in 2D materials. SHG measurements in MoTe2 are also demonstrated as an efficient way to distinguish the 2H‐to‐1T′ phase transition. Compared with the SHG in 2H‐MoTe2, 1T′‐MoTe2's SHG has much lower efficiency and the polarization dependence is changed from a six‐fold pattern to a two‐lobe pattern. [ABSTRACT FROM AUTHOR]

Abstract: Optical second harmonic generations (SHGs) from atomically thin MoTe2 flakes with 2H and 1T′ phases are studied. From 2H‐MoTe2 samples with odd (even) numbers of layers, strong (negligible) SHGs are observed due to the layer‐dependent broken inversion symmetry. When pumped by a telecom‐band laser, SHG from a monolayer 2H‐MoTe2 is about one order of magnitude stronger than that from a monolayer WS2; an extremely high second‐order nonlinear susceptibility of 2.5 nm V−1 is estimated, presenting the highest value among those reported in 2D materials. SHG measurements in MoTe2 are also demonstrated as an efficient way to distinguish the 2H‐to‐1T′ phase transition. Compared with the SHG in 2H‐MoTe2, 1T′‐MoTe2's SHG has much lower efficiency and the polarization dependence is changed from a six‐fold pattern to a two‐lobe pattern. [ABSTRACT FROM AUTHOR]

The G protein-coupled estrogen receptor (GPER) has been implicated in the regulation of smooth muscle cell (SMC) proliferation. The GPER selective agonist G-1 has been a useful tool for exploring the biological roles of GPER in a variety of experimental settings, including SMC proliferation. The present study, originally designed to investigate cellular and signaling mechanisms underlying the regulatory role of GPER in vascular SMC proliferation using G-1, unexpectedly revealed off-target effects of G-1. G-1(1-10 μM) inhibited bromodeoxyuridine (BrdU) incorporation of human SMCs and caused G2/M cell accumulation. G-1 treatment also increased mitotic index concurrent with a decrease in phosphorylation of Cdk1 (Tyr 15) and an increase in phosphorylation of the mitotic checkpoint protein BuBR1. Furthermore, G-1 caused microtubule disruption, mitotic spindle damage, and tubulin depolymerization. G-1 induced cell apoptosis as indicated by the appearance of TUNEL-positive and annexin V-positive cells with enhanced cleavage of caspases 3 and 9. However, neither the GPER antagonist G-15 nor the MAPK kinase inhibitor PD98059 prevented these G-1 effects. Down-regulation of GPER or p44/42 MAPK with siRNA transfection also did not affect the G-1-induced apoptosis. We conclude that G-1 inhibits proliferation of SMCs through mechanisms involving mitotic arrest and apoptosis, independent of GPER and the MAPK pathway. J. Cell. Physiol. 230: 885-895, 2015. © 2014 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Integrated 2-dimensional (2D) photonic devices such as monolayer waveguide has generated exceptional interest because of their ultimate thinness. In particular, they potentially permit stereo photonic architecture through bond-free van der Waals integration. However, little is known about the coupling and controlling of the single-atom guided wave to its photonic environment, which governs the design and application of integrated system. Here, we report the optical coupling of atomically guided waves to other photonic modes. We directly probe the mode beating between evanescent waves in a monolayer 2D waveguide and a silicon photonic waveguide, which constitutes a vertically integrated interferometer. The mode-coupling measures the dispersion relation of the guided wave inside the atomic waveguide and unveils it strongly modifies matter's electronic states, manifesting by the formation of a propagating polariton. We also demonstrated light modulating and spectral detecting in this compact nonplanar interferometer. These findings provide a generalizable and versatile platform toward monolithic 3-dimensional integrated photonics., (Copyright © 2024 Yue Wang et al.)

Two-dimensional (2D) materials, featuring distinctive electronic and optical properties and dangling-bond-free surfaces, are promising for developing high-performance on-chip photodetectors in photonic integrated circuits. However, most of the previously reported devices operating in the photoconductive mode suffer from a high dark current or a low responsivity. Here, we demonstrate a MoTe 2 p - i - n homojunction fabricated directly on a silicon photonic crystal (PC) waveguide, which enables on-chip photodetection with ultralow dark current, high responsivity, and fast response speed. The adopted silicon PC waveguide is electrically split into two individual back gates to selectively dope the top regions of the MoTe 2 channel in p - or n -types. High-quality reconfigurable MoTe 2 ( p - i - n , n - i - p , n - i - n , p - i - p ) homojunctions are realized successfully, presenting rectification behaviors with ideality factors approaching 1.0 and ultralow dark currents less than 90 pA. Waveguide-assisted MoTe 2 absorption promises a sensitive photodetection in the telecommunication O-band from 1260 to 1340 nm, though it is close to MoTe 2 's absorption band-edge. A competitive photoresponsivity of 0.4 A/W is realized with a light on/off current ratio exceeding 10 4 and a record-high normalized photocurrent-to-dark-current ratio of 10 6 mW -1 . The ultrasmall capacitance of p - i - n homojunction and high carrier mobility of MoTe 2 promise a high dynamic response bandwidth close to 34.0 GHz. The proposed device geometry has the advantages of employing a silicon PC waveguide as the back gates to build a 2D material p - i - n homojunction directly and simultaneously to enhance light-2D material interaction. It provides a potential pathway to develop 2D material-based photodetectors, laser diodes, and electro-optic modulators on silicon photonic chips.