Airborne ultrasound pulse amplification based on acoustic resonance switching.

Airborne ultrasound radiation pressure, a nonlinear effect that appears as a static force in mid-air in the presence of strong ultrasound, has recently been applied in novel scientific and industrial fields. However, the output power of an ultrasound transducer remains low mainly due to the significant mismatch in acoustic impedance between a solid diaphragm and air. To circumvent this fundamental challenge, we propose to emit amplified airborne ultrasound pulses by instantaneously releasing stored acoustic energy into free-space.

High-Speed and On-Chip Optical Switch Based on a Graphene Microheater.

Graphene is a promising material for producing optical devices because of its optical, electronic, thermal, and mechanical properties. Here, we demonstrated on-chip optical switches equipped with a graphene heater, which exhibited high modulation speed and efficiency. We designed the optimal structure of the optical switch with an add/drop-type racetrack resonator and two output waveguides (the through and drop ports) by the electromagnetic field calculation.

Sub-terahertz vortex beam generation using a spiral metal reflector.

We demonstrate sub-terahertz vortex beam generation using a spiral metal reflector that can be used for both polarizations. A vortex beam is a ring-shaped beam that possesses sub-wavelength null in the center formed by angular phase variation. While the sub-terahertz vortex beams have gained increasing attention for a wide range of applications in sensing and communications, techniques for generating them are still accompanied by challenges.

In Situ Formation of Slippery-Liquid-Infused Nanofibrous Surface for a Transparent Antifouling Endoscope Lens.

Slippery-liquid-infused porous surfaces (SLIPS) are state-of-the-art materials owing to their excellent properties derived from their fluidity (e.g., dynamic omniphobicity and self-healing function).

A new 'sticking' coating method for the in situ formation of nanofiber networks on micrometer to millimeter-sized surfaces.

A simple versatile method to form a nanofiber coating in situ on micrometer to millimeter-sized surfaces is developed. A fiber-filled porous sheet is designed by electrospinning a dense polymer solution on a patterned PET/aluminum alloy collector. By sticking the small area surface onto a fiber-filled porous sheet, a nanofiber-coated small area surface is obtained, which overcomes conventional nanofiber coating difficulties.