We have developed a broadband ultra-sensitive infrared (IR) sensor with novel folded gold nanoantenna sensing array on calcium fluoride (CaF2) substrate integrated with microfluidic channel, which will allow continuous monitoring wideband fingerprint IR absorption of liquid and solution using enhancement of plasmonic nanoantenna. The broadband detection window achieved is over 10 times larger than single nanorod antenna array, which pave the way to real-time fingerprint monitoring and various molecular recognition. Our device can be applied on label-free and real-time sensing of gas, liquid as well as biomolecules for various applications such as environmental monitoring, healthcare, and clinical diagnosis.
The high sensitivity of plasmonic sensors can help to improve the detection limits of molecules with ultra-low concentration. A hook-shape nanoantenna structure is developed in this work to achieve high sensitivity.
For sensing array, 16 pixels of hook-shaped folded gold antenna arrays with increasing of various lengths are used to form different resonant wavelengths. For supercell, 16 hook-shaped folded antennas are used to create a unit cell with multiple resonant wavelengths. By repeating the unit cell with a specific period, broadband multipeak sensing supercell is generated. Therefore, continuous broadband excitation of both array and supercell can be achieved.
The broadband ultrasensitive plasmonic sensors have the potential in multiple gas sensing such as CO2, NOx and SOx. It can also detect volatile organic compound (VOC) like acetone, ethanol, isoprene and etc. Therefore, it can be used for environmental monitoring such air quality and pollution, healthcare monitoring and disease diagnostic.
Our plasmonic sensors have the advantages of compact size, fast response time, compatibility for nano integration, which bring the potential for the wearable Internet of Things (IoT) sensor applications such as environmental monitoring, air quality and pollution monitoring, healthcare, and clinical diagnostics. Our device allows high sensitivity in multiple chemical sensing.