Weixin Liu

• National University of Singapore

Photonic neural networks (PNNs) based on silicon photonic integrated circuits (Si‐PICs) offer significant advantages over microelectronic counterparts, including lower energy consumption, higher bandwidth, and faster computing speeds. However, the analog nature of optical signal in PNNs makes Si‐PIC solutions highly sensitive to device noise, espec...

Piezo-optomechanics presents a promising route to convert microwave signals to the optical domain, implementing processing tasks that are challenging using conventional electronics. The surge of integrated photonics facilitates the exploitation of localized light-sound interactions toward new technological paradigms. However, the efficient acousto-...

Molecular identification of volatile organic compounds (VOCs) plays an important role in various applications including environmental monitoring and smart farming. Mid‐infrared (MIR) fingerprint absorption spectroscopy is a powerful tool to extract chemical‐specific features for gas identification. However, the detection and recognition of trace VO...

Bio/chemical mixture sensing in a water environment is of great importance in sensing applications. Relying on plentiful molecular fingerprints in mid‐infrared (MIR) and high integration potential, nanophotonic waveguide‐based MIR lab‐on‐a‐chip (LoC) provides a miniaturized and versatile solution for specific and label‐free bio/chemical detection....

On‐chip nanophotonic waveguide sensor is a promising solution for miniaturization and label‐free detection of gas mixtures utilizing the absorption fingerprints in the mid‐infrared (MIR) region. However, the quantitative detection and analysis of organic gas mixtures is still challenging and less reported due to the overlapping of the absorption sp...

In recent years, with the further ministration of the semiconductor device in integrated circuits, power consumption and data transmission bandwidth have become insurmountable obstacles. As an integrated technology, photonic integrated circuits (PICs) have a promising potential in the post‐Moore era with more advantages in data processing, communic...

The reliable function in vivo of self‐powered implantable bioelectric devices (iBEDs) requires biocompatible, seamless, effective interactions with biological tissues. Herein, an implantable tissue‐adhesive piezoelectric soft sensor (TPSS), in which the piezoelectric sensor converts biomechanical signals into electrical signals, and the adhesive hy...

Graphene has attracted great interest for integrated photonic platforms in the long‐wave infrared (LWIR) for spectroscopic and polarimetric sensing due to the capability of on‐chip integration, fast response, and broadband operation. However, graphene suffers from low photoresponsivity and thus poor sensing performance due to weak absorption. Polar...

As miniaturized solutions, mid-infrared (MIR) waveguide sensors are promising for label-free compositional detection of mixtures leveraging plentiful absorption fingerprints. However, the quantitative analysis of liquid mixtures is still challenging using MIR waveguide sensors, as the absorption spectrum overlaps for multiple organic components acc...

Mid‐infrared spectroscopy is an emerging technique in various applications such as molecule identification and label‐free chemical sensing. Integrated photonic platforms have a promising potential to perform miniaturized spectroscopic sensing with the advantage of compact footprint, low cost, and low power consumption. As an essential building bloc...

Long-wave infrared (LWIR, 6–14 µm) is an important wavelength range as it covers abundant vibrational molecular fingerprints that can be used for gas/liquid sensing and absorption spectroscopy. Silicon waveguide-based passive photonic devices that offer advantages toward chip-scale miniaturization of photonic integrated circuits (PIC) and photonic...

Nanophotonic waveguides that implement long optical pathlengths on chips are promising to enable chip-scale gas sensors. Nevertheless, current absorption-based waveguide sensors suffer from weak interactions with analytes, limiting their adoptions in most demanding applications such as exhaled breath analysis and trace-gas monitoring. Here, we prop...

With the fast development of energy harvesting technology, micro-nano or scale-up energy harvesters have been proposed to allow sensors or internet of things (IoT) applications with self-powered or self-sustained capabilities. Facilitation within smart homes, manipulators in industries and monitoring systems in natural settings are all moving towar...

Optomechanical sensing based on the coupling between mechanical motions and optical resonances has attracted huge interest in sensor applications due to its small footprint, high sensitivity, low detection limit, and electromagnetic immunity. Optomechanical sensors that detect from mechanical motion at µm scale to molecular vibration at nm scale ha...

Long-wave infrared (LWIR, 6–14 µm) processes enormous potential for chem/biosensing as it covers abundant molecular absorption fingerprints. Waveguides provide an attractive chip-scale miniaturization solution for optical sensors. However, the exploration of waveguide sensors in this wavelength range is limited. Here, an LWIR photonic platform for...

A conversion from mechanical energy into direct current (DC) is of great interest to realize the next-generation self-sustained Internet of Things (IoT) and real-time virtual reality (VR) control. Inspired by ancient waterwheel transport water and P–N junction theory, a continuous DC nanogenerator was developed using charges unidirectional transpor...

With the fast development of the fifth-generation cellular network technology (5G), the future sensors and microelectromechanical systems (MEMS)/nanoelectromechanical systems (NEMS) are presenting a more and more critical role to provide information in our daily life. This review paper introduces the development trends and perspectives of the futur...

Respiratory rate is a vital physiological signal in laboratory rodents research. This paper presents a noninvasive method based on resonant humidity sensor for monitoring respiratory rate of rats. The sensor is composed of an aluminum nitride (AlN) resonant microcantilever coated with graphene oxide (GO) film. The sensor shows high sensitivity and...

This paper reports an aerosol sensor for PM1 monitoring based on a virtual impactor (VI) and a surface acoustic wave (SAW) sensor. The VI is fabricated using three-dimensional (3D) printing techniques for PM1 classification and a SAW sensor is put at the VI major flow outlet to detect PM1 particles mass. The pressure and flow distribution of the VI...