Single-molecule fluorescence techniques have revolutionized our ability to study proteins. However, the presence of a fluorescent label can alter the protein structure and/or modify its reaction with other species. To avoid the need for a fluorescent label, the intrinsic autofluorescence of proteins in the ultraviolet offers the benefits of fluorescence techniques without introducing the labelling drawbacks. Unfortunately, the low autofluorescence brightness of proteins has greatly challenged single molecule detection so far. Here we introduce optical horn antennas, a dedicated nanophotonic platform enabling the label-free detection of single proteins in the UV. This design combines fluorescence plasmonic enhancement, efficient collection up to 85° angle and background screening. We detect the UV autofluorescence from immobilized and diffusing single proteins, and monitor protein unfolding and dissociation upon denaturation. Optical horn antennas open up a unique and promising form of fluorescence spectroscopy to investigate single proteins in their native states in real time.

This paper presents a simulated design of millimeter wave square patch antenna 1×6 array on silicon and Roger RO4003 substrate for prominent multiple bands i.e. 58GHz-60GHz, 65GHz-68GHz, 72GHz-77GHz. Designed antenna can serve 5G cellular network as well as advance device-to-device (D2D) network which is special feature of 5G communication system to reduce end-to-end latency and to implement Mission Critical Push-To-Talk Communication (MCPTT) and Vehicle-to-Anything (V2X) Communication. Designed antenna has peakgain of 9 dB and very high efficiency. Return loss for given bands at their resonant frequencies are as low as -35dB and total bandwidth of 9.57 GHz. Silicon is used under feeding network to enhance the bandwidth and reduce the size of feeding network and low dielectric material under patch to reduce dielectric loss thus maintaining the efficiency. Symmetrical parallel feeding network is used to enhance gain. Inset fed with quarter wave transformers are used for feeding and matching, along with maintaining the conformity. A novel design is used to kill the spurious radiation due to feed network, thus shaping the radiation pattern for cellular application. Overall size of antenna is 6.7mm×30mm×1.2mm compatible with miniaturized devices and is printable.

Nanoapertures milled in metallic films called zero-mode waveguides (ZMWs) overcome the limitations of classical confocal microscopes by enabling single molecule analysis at micromolar concentrations with improved fluorescence brightness.