OptoGPT: A foundation model for inverse design in optical multilayer thin film structures

Optical multilayer thin film structures have been widely used in numerous photonic applications.However,existing inverse design methods have many drawbacks because they either fail to quickly adapt to different design targets,or are difficult to suit for different types of structures,e.g.,designing for different materials at each layer.These methods also cannot accommodate versatile design situations under different angles and polarizations.In addition,how to benefit practical fabrications and manufacturing has not been extensively considered yet.In this work,we introduce OptoGPT(Opto Generative Pretrained Transformer),a decoder-only transformer,to solve all these drawbacks and issues simultaneously.

Benchmarking deep learning-based models on nanophotonic inverse design problems

Photonic inverse design concerns the problem of finding photonic structures with target optical properties.However,traditional methods based on optimization algorithms are time-consuming and computationally expensive.Recently,deep learning-based approaches have been developed to tackle the problem of inverse design efficiently.Although most of these neural network models have demonstrated high accuracy in different inverse design problems,no previous study has examined the potential effects under given constraints in nanomanufacturing.Additionally,the relative strength of different deep learning-based inverse design approaches has not been fully investigated.Here,we benchmark three commonly used deep learning models in inverse design:Tandem networks,Variational Auto-Encoders,and Generative Adversarial Networks.We provide detailed comparisons in terms of their accuracy,diversity,and robustness.We find that tandem networks and Variational Auto-Encoders give the best accuracy,while Generative Adversarial Networks lead to the most diverse predictions.Our findings could serve as a guideline for researchers to select the model that can best suit their design criteria and fabrication considerations.In addition,our code and data are publicly available,which could be used for future inverse design model development and benchmarking.

Functional plastic films:nano-engineered composite based flexible microwave antennas with near-unity relative visible transmittance

Microwave antennas are essential elements for various applications,such as telecommunication,radar,sensing,and wireless power transport.These antennas are conventionally manufactured on rigid substrates using opaque materials,such as metal strips,metallic tapes,or epoxy pastes;thus,prohibiting their use in flexible and wearable devices,and simultaneously limiting their integration into existing optoelectronic systems.Here,we demonstrate that mechanically flexible and optically transparent microwave antennas with high operational efficiencies can be readily fabricated using composite nanolayers deposited on common plastic substrates.The composite nanolayer structure consists of an ultra-thin copper-doped silver film sandwiched between two dielectric films of tantalum pentoxide and aluminum oxide.The material and thickness of each constituent layer are judiciously selected such that the whole structure exhibits an experimentally measured averaged visible transmittance as high as 98.94%compared to a bare plastic substrate,and simultaneously,a sheet resistance as low as 12.5Ω/sq.Four representative types of microwave antennas are implemented:an omnidirectional dipole antenna,unidirectional Yagi-Uda antenna,low-profile patch antenna,and Fabry-Pérot cavity antenna.These devices exhibit great mechanical flexibility with bending angle over 70°,high gain of up to 13.6 dBi,and large radiation efficiency of up to 84.5%.The proposed nano-engineered composites can be easily prepared over large areas on various types of substrates and simultaneously overcome the limitations of poor mechanical flexibility,low electrical conductivity,and reduced optical transparency usually faced by other constituent materials for flexible transparent microwave antennas.The demonstrated flexible microwave antennas have various applications ranging from fifth-generation and vehicular communication systems to bio-signal monitors and wearable electronics.

Decorative near-infrared transmission filters featuring high-efficiency and angular-insensitivity employing ID photonic crystals

We present a new scheme for visibly-opaque but near-infrared-transmitting filters involving 7 layers based on one-dimensional ternary photonic crystals, with capabilities in reaching nearly 100% transmission efficiency in the near-infrared region. Different decorative reflection colors can be created by adding additional three layers while maintaining the near-infrared transmission performance. In addition, our proposed structural colors show great angular insensitivity up to ±60° for both transverse electric and transverse magnetic polarizations, which are highly desired in various fields. The facile strategy described here involves a simple deposit!on method for the fabrication, thereby having great potential in diverse applications such as image sensors, anti-counterfeit tag, and optical measurement systems.

Inverse design of metasurface optical filters using deep neural network with highdegrees of freedom

In order to obtain a metasurface structure capable of filtering light of a specific wavelength range in the visible band,the traditional methods usually traverse the space consisting of possible designs,searching for a potenti ally satisfactory structure by performing iterative calculations to solve Maxwell's equations.In this article,we propose a systematic method based on neural networks that can complete an inverse design process to solve the problem.Compared with the traditional methods,our method is much faster while competent to encom-pass a high degree of freedom to generate device structures,which can ensure that the spectra of generated structures resemble the desired ones.

Quasi-vertical tapers for polymer-waveguide-based interboard optical interconnects

A mode transformer based on the quasi-vertical taper is designed to enable high coupling efficiency for interboardlevel optical interconnects involving single-mode polymer waveguides and standard single-mode fibers. A triangular region fabricated above the waveguide is adopted to adiabatically transform the mode from the fiber into the polymer waveguide. The effects of the geometrical parameters of the taper, including width, height, tip width,etc., on the coupling efficiency are numerically investigated. Based on this, a quasi-vertical taper for the polymer rib waveguide system is designed, fabricated, and characterized. Coupling losses of 1.79 0.30 and 2.23 0.31 dB per coupler for the quasi-TM and quasi-TE mode, respectively, are measured across the optical communication C and L bands(1535 to 1610 nm). Low-cost packaging, leading to widespread utilization of polymeric photonicdevices, is envisioned for optical interconnect applications.

使用微环谐振器和激光产生的超声聚焦的超声检测和成像

超声的光学检测是基于应变场与光场的相互作用的新兴技术,通过调节谐振腔的光学特性进行高灵敏检测。与传统的压电换能器相比,这种检测方案具有宽频带响应,以及灵敏度与尺寸无关的优点。检测器的高灵敏度对于较深的穿透深度至关重要,特别是对于高分辨率成像,因为检测物对高频超声波有强衰减。此外,小器件尺寸具有在超声检测中实现宽接受角的优势。介绍了基于聚合物光子微环谐振器的超声波高灵敏度和宽带检测,并展示其在高分辨率光声层析与光声显微技术中的应用。类似原理还可应用于太赫兹检测,微环可以"听到"吸收太赫兹能量的纳米材料产生的声波。还介绍了产生和聚焦超声波的薄膜光学发射器,用于强振幅聚焦超声成像与治疗。光声源由碳纳米管和弹性体聚合物制成。纳米复合材料作为优异的光吸收器和高效的热转化器,可以产生具有强振幅的输出压力,并具有显示出高频特性的对应频谱。这种方法可以为收集和图形化等细胞工程提供多功能的工具,更重要的是,非热破坏裂可以促进靶向细胞的药物输运与基因治疗。

Optical enhancement effects of plasmonic nanostructures on organic photovoltaic cells

In this article, the optical enhancement effects of plasmonic nanostructures on OPV cells were reviewed as an effective way to resolve the mismatch problems between the short exciton diffusion length in organic semiconductors （around 10 nm） and the large thickness required to fully absorb sunlight （e.g. hundreds of nanometers）. Especially, the performances of OPVs with plasmonic nanoparticles in photoactive and buffer layers and with periodic nanostructures were investigated. Furthermore, nanoimprint lithography-based nanofabrication processes that can easily control the dimension and uniformity of structures for large-area and uniform I^lasmonic nanostructures were demonstrated.