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Surface plasmon resonance (SPR) sensors are based on photon-excited surface charge density oscillations confined at metal-dielectric interfaces, which makes them highly sensitive to biological or chemical molecular bindings to functional metallic surfaces. Metal nanostructures further concentrate surface plasmons into a smaller area than the diffraction limit, thus strengthening photon-sample interactions. However, plasmonic sensors based on intensity detection provide limited resolution with long acquisition time owing to their high vulnerability to environmental and instrumental noises. Here, we demonstrate fast and precise detection of noble gas dynamics at single molecular resolution via frequency-comb-referenced plasmonic phase spectroscopy. The photon-sample interaction was enhanced by a factor of 3,600 than the physical sample thickness owing to plasmon resonance and thermophoresis-assisted optical confinement effects. By utilizing a sharp plasmonic phase slope and a high heterodyne information carrier, a small atomic-density modulation was clearly resolved at 5 Hz with a resolution of 0.06 Ar atoms per nano-hole (in 10− 11 RIU) in Allan deviation at 0.2 s; a faster motion up to 200 Hz was clearly resolved. This fast and precise sensing technique can enable the in-depth analysis of fast fluid dynamics with the utmost resolution for a better understanding of biomedical, chemical, and physical events and interactions.

A terahertz frequency synthesizer is devised with reference to an ultra-stable cavity via an optical comb with an unprecedented stability of 310-15 at 1-s averaging.

We perform comb-to-comb stabilization through a 1.3-km free-space optical link. The achieved frequency stability is 1.22×10−15 at 1.0 s integration over the entire comb spectrum.

Stable terahertz sources are required to advance high precision terahertz applications such as molecular spectroscopy, terahertz radars, and wireless communications. Here, we demonstrate a photonic scheme of terahertz synthesis using an optical comb in stabilization to an ultra-low expansion optical cavity offering a 15-digit accuracy. By heterodyne photomixing of comb lines, terahertz frequencies of 0.10 – 1.10 THz are synthesized with a 2-mHz linewidth and a fractional instability of 3.26×10-15 at 1.3-s integration. Compared to other state-of-the-art counterparts, our terahertz synthesizer offers a fine frequency tuning capability in steps of 100 MHz and an extremely low level of phase noise below -70 dBc/Hz even at 1 Hz offset. Such unprecedented performance is expected to drastically improve the signal-to-noise ratio of terahertz radars, the resolving power of terahertz molecular spectroscopy, and the transmission capacity of wireless communications.

We propose a centrifuge-based microfluidic device housed in a standard microtube for generation of monodisperse microdroplets from tens of $\mu \mathrm{l}$ sample volume. Centrifugation drives overpressure of a dispersed phase, thus infuses the dispersed phase into a microchannel. Because of the channel geometry for step emulsification, the infused dispersed phase is pinched off forming droplets. Then, the droplets accumulate on the bottom of the microtube by centrifugal force. We succeeded in generation of monodisperse droplets with a diameter of $130\ \mu\mathrm{m}(\mathrm{CV} by operation of centrifuge. Since the device can produce droplets in a microtube without complex experimental setup (e.g. syringe pump), it will be a powerful tool for simple generation of droplets for droplet-based applications.

Monodisperse picoliter droplets have been widely used for biochemical reactors and preparation of functional microbeads for food, cosmetics, and medical industry. Although conventional microfluidic technologies enable the production of monodisperse picoliter droplets, special instruments (e.g. syringe pump) are required, leading to its poor usability and accessibility in other research fields. In this study, we propose centrifuge-based step emulsification device housed in a microtube for simple and fast generation of monodisperse picoliter droplets. Our device consists of a reservoir part for storage of the dispersed phase and a microchannel part for droplet formation. Centrifugation using a commercial centrifuge exerts excessive pressure on the dispersed phase, infusing it into a microchannel. The infused dispersed phase is pinched off, forming droplets due to the channel geometry for step emulsification. The produced droplets at the step then are transported to the bottom of the microtube due to the centrifugal force. Using this device, we achieved formation of monodisperse water-in-oil (W/O) picoliter droplets with diameters ranging from 18 to 90 μm. Moreover, we demonstrated the cell-free protein synthesis reaction in monodisperse picoliter droplets as well as the production of cell-sized glucose-responsive hydrogel microbeads. We believe that our device would be a powerful tool for simple and fast preparation of picoliter samples with high usability.

In this paper, we developed a centrifugal emulsification device toward high-throughput generation of monodisperse liposomes. The device generated lipid vesicles in two steps, membrane emulsification by asymmetric through-holes on a plate, and transfer of the emulsions to a planar monolayer at an oil/water interface. As a result of centrifugation of the device in a microtube, we succeeded in collection of cell-sized lipid vesicle. Since a number of the asymmetric through-holes can be fabricated on the plate by standard photolithographic process, and the reservoir for inner solution has relatively large volume (40 μl), the proposed device will be a powerful tool for massive generation of liposomes.