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Enhanced Second Harmonic Generation from Ferroelectric HfO <sub/>2</sub> -Based Hybrid Metasurfaces
摘要： Integrated nonlinear metasurfaces leading to high-efficiency optical second harmonic generation (SHG) are highly desirable for optical sensing, imaging, and quantum photonic systems. Compared to traditional metal-only metasurfaces, their hybrid counterparts, where a non-centrosymmetric nonlinear photonic material is incorporated in the near field of a metasurface, they can significantly boost SHG efficiency. However, it is difficult to integrate such devices on-chip due to material incompatibilities, thickness scaling challenges and the narrow band gaps of nonlinear optical materials. Here, we demonstrate significantly enhanced SHG in on-chip integrated metasurfaces by using nanometer thin films of ferroelectric Y:HfO2. This material has the merit of CMOS compatibility, ultra-violet transparency up to 250 nm and significant scalability down to sub 10 nm when deposited on silicon. We observe a twenty times magnitude enhancement of the SHG intensity from the hybrid metasurface compared to a bare ferroelectric HfO2 thin film. Moreover, a 3-fold SHG enhancement is observed from the hybrid metasurface compared to a control structure using non-ferroelectric HfO2, demonstrating a major contribution to the SHG signal from ferroelectric Y:HfO2. The effective second-order nonlinear optical coefficient χ(2) of Y:HfO2 is determined to be 6.0 ± 0.5 pm/V, which is comparable to other complex nonlinear photonic oxide materials. Our work provides a general pathway to build an efficient on-chip nanophotonic nonlinear light source for SHG using ferroelectric HfO2 thin films.
关键词： second harmonic generation (SHG),nonlinear photonics,metasurface,plasmonics,ferroelectric Y:HfO2
更新于2025-09-23 15:23:52
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Nonlinear Optical Properties of CdS Semiconductor nanowires
摘要： In this work, we report on the nonlinear optical properties in single Cadmium sulfide nanowires (CdS NWs). The high qulity growth of CdS semiconductor nanowires were synthesized by chemical vapor deposition (CVD) method. The as-obtained products were characterized by X-ray diffraction (XRD) , Scanning electron microscopy (SEM), and the energy dispersive X-ray spectrom (EDS) was used to determine the specific elemental distribution and show purity of the CdS semiconductor nanowires . The excitation of femtosecond laser(800 nm, 50 fs, 80 MHz) was used to study the nonlinear optical properties of CdS nanowires, such as the Second Harmonic Generation(SHG) and optical waveguide effect. CdS NW has a second harmonic generation with a blue emission bands at a wavelength of 400 nm . Finally, based on the dark field image of the CCD taken and combined with the spectrum, it is proved that CdS NW has an optical waveguide effect.
关键词： Cadmium sulfide (CdS),Waveguide,nanowires (NWs),Second- Harmonic Generation (SHG),Chemical Vapor Deposition (CVD)
更新于2025-09-19 17:15:36
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Rb <sub/>10</sub> Zn <sub/>4</sub> Sn <sub/>4</sub> S <sub/>17</sub> : A Chalcogenide with Large Laser Damage Threshold Improved from the Mn-Based Analogue
摘要： In the military and civilian fields, with the development of new technologies, high-powered nonlinear optical (NLO) crystals demonstrate broad application prospects. For purposes of designing a better NLO material, a new chalcogenide Rb10Zn4Sn4S17 was successfully designed with a high temperature solid-state method on the basis of previously reported compound Sr3MnSn2S8. The experimental results indicate that Rb10Zn4Sn4S17 possesses a prominent band gap of 3.59 eV, compared with the laser damage threshold (LDT) of Sr3MnSn2S8 (3 times that of AgGaS2); Rb10Zn4Sn4S17 shows an outstanding LDT about 5 times that of AgGaS2. Meanwhile, it has an ideal second harmonic generation (SHG) response approximately 0.7 times that of AgGaS2.
关键词： second harmonic generation (SHG),laser damage threshold (LDT),chalcogenide,nonlinear optical (NLO) crystals
更新于2025-09-19 17:13:59
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Second Harmonic Generation for Moisture Monitoring in Dimethoxyethane at a Gold-Solvent Interface Using Plasmonic Structures
摘要： Second harmonic generation (SHG) is forbidden from most bulk metals because metals are characterized by centrosymmetric symmetry. Adsorption or desorption of molecules at the metal interface can break the symmetry and lead to SHG responses. Yet, the response is relatively low, and minute changes occurring at the interface, especially at solid/liquid interfaces, like in battery electrodes are difficult to assess. Herein, we use a plasmonic structure milled in a gold electrode to increase the overall SHG signal from the interface and gain information about small changes occurring at the interface. Using a specific homebuilt cell, we monitor changes at the liquid/electrode interface. Specifically, traces of water in dimethoxyethane (DME) have been detected following changes in the SHG responses from the plasmonic structures. We propose that by plasmonic structures this technique can be used for assessing minute changes occurring at solid/liquid interfaces such as battery electrodes.
关键词： second-order nonlinear susceptibility,second harmonic generation (SHG),plasmonic enhancement,battery
更新于2025-09-16 10:30:52
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Anapole Resonances Facilitated by High Index Contrast between Substrate and Dielectric Nanodisk Enhance Vacuum Ultraviolet Generation
摘要： Anapole modes are known to be excited only in high-index nanoparticles. Here we show that the nanodisks made of dielectric materials with much lower refractive indices, such as LiNbO3, can generate anapole modes, provided that they are supported by metallic or near-zero-index substrate. The important parameter for exciting anapole mode is the index contrast between nanodisk and substrate, rather than the refractive index of the nanodisk. We numerically demonstrate highly efficient coherent generation of vacuum ultraviolet with the efficiency higher than 10-2 % based on the second-harmonic generation via the excitation of anapole modes in LiNbO3 nanodisks supported by aluminum substrate. Highly efficient vacuum ultraviolet nanosource proposed in this work can find important applications for spectroscopic and sensing purposes at the nanoscale.
关键词： Second-harmonic generation (SHG),Anapole mode,Refractive index,Nanodisks,Vacuum ultraviolet (VUV)
更新于2025-09-09 09:28:46