Search

Half-wave plate (HWP) is one of the key polarization controlling devices in optical systems. The conventional HWPs based on birefringent crystals are inherently bulky and difficult to be monolithically integrated with other optical components. In this work, metasurface-based HWPs with high compactness are demonstrated on a 12-inch silicon complementary metal-oxide-semiconductor platform. Three-dimensional finite difference time domain simulation is used to design the nanostructure and investigate the impact of fabrication process variation on the device performance. In addition, the cross- and co-polarization transmittance (Tcross and Tco) of the HWPs located at different wafer locations are characterized experimentally. The peak Tcross and valley Tco values of 0.69 ± 0.053 and 0.032 ± 0.005 are realized at the wavelength around 1.7 μm, respectively. This corresponds to a polarization conversion efficiency of 95.6% ± 0.8%.

Metasurface-based beam deflector, as an important optical element to bend the light propagation direction, has drawn a lot of interests in research to achieve miniaturization of devices and reduction of system complexity. Based on the 12-inch immersion lithography technology, in this work, an ultra-thin and large-area pixelated metasurface beam deflector with a footprint of 2500 × 2500 μm, formed by nanopillars with diameters from 221 to 396 nm, is demonstrated on a 12-inch glass wafer. The 21 × 21 array of deflectors is designed to bend the input light in different directions and to generate 441 random points. In addition, the layer transfer on the 12-inch glass wafer makes the device working in transmission mode at a 940-nm wavelength. The random point array generated from the experiment shows good match with the design. This pixelated metasurface beam deflector can generate random points simultaneously and has potential to make beam steering by switching each pixel of the beam deflector, which can be applied on motion detection, facial recognition, and light detection and ranging.

Acoustically actuated magnetoelectric (ME) antennas utilize acoustic wave resonance to complete the process of receiving and transmitting signals, which promotes the development of antenna miniaturization technology. This paper presents a bilayer magnetostrictive/AlN ME laminated antenna. The proposed laminated antenna uses the FeGa/FeGaB bilayer materials as magnetostrictive materials, which combine the advantages of soft magnetic properties of FeGa and the low loss of FeGaB. First, multiphysics modeling and analysis are performed for the proposed ME laminated antenna by finite element method (FEM). The positive/inverse ME effects and the influences of the volume ratio of the FeGa/FeGaB bilayer on the antenna performance are studied. The results show that the output voltage and ME coefficient of the FeGa/FeGaB bilayer magnetostrictive material with a volume ratio of 1:1 are 3.97 times and 195.8% higher than that of the single FeGaB layer, respectively. The eddy current loss is 52.08% lower than that of single-layer FeGa. According to the surface equivalence principle, the far-field radiation process is simulated. The results show that the gain of the ME antenna is 15 dB larger than that of the same-size micro-loop antenna, and the gain of the ME antenna is about −44.9 dB. The improved performance and magnetic tunability of the proposed bilayer magnetostrictive materials make ME antennas excellent candidates for portable devices and implantable medical devices. [ABSTRACT FROM AUTHOR]

In robotic‐assisted minimally invasive surgery (RMIS), non‐sentient surgical instruments make it impossible for surgeons to perceive operational force during the procedure. To facilitate surgeons with force telepresence during surgery, a highly integrated MEMS‐based piezoresistive 3D force sensing module, which is composed of a MEMS‐based piezoresistive sensor chip, an encapsulation cap with miniature pyramids, and a top elastic layer, is demonstrated. This innovative combined construction allows for rapid replacement of elastic layers with different thicknesses and different Young's modulus, so as to realize an adjustable sensitivity and measurement range for different surgeries. By replacing the elastic layer, the same amount of change in resistance can be achieved for external force of 3 and 10 N in the Z‐axis; the sensitivity in X‐ and Y‐axes can be increased by a maximum of eight and seven times, respectively. Meanwhile, miniature size enables it to be integrated into various surgical instruments' tip. Experimental demonstrations involving palpation simulated nodule detection of kidney, ex vivo puncture, and threading forces estimation of tissue‐mimicking are conducted to validate the effectiveness of adjusting sensitivity and range. This sensing module is potentially a promising solution for low‐cost and versatility to surgical instruments, which can facilitate unification of force‐sensing/intelligent surgical instruments. [ABSTRACT FROM AUTHOR]

This paper reports on the fabrication and test of a hydrogel-actuated microvalve that responds to changes in the concentration of specific chemical species in an external liquid environment. The microvalve consists of a thin hydrogel, sandwiched between a stiff porous membrane and a flexible silicone rubber diaphragm. Swelling and deswelling of the hydrogel, which results from the diffusion of chemical species through the porous membrane is accompanied by the deflection of the diaphragm and hence closure and opening of the valve intake orifice. A phenylboronic-acid-based hydrogel was used to construct a smart microvalve that responds to the changes in the glucose and pH concentrations. The fastest response time (for a pH concentration cycle) achieved was 7 min using a 30-[micro]m-thick hydrogel and a 60-[micro]m-thick porous membrane with 0.1 [micro]m pore size and 40% porosity. [932] Index Terms--Drug delivery, hydrogel, microfluidics, microvalve, smart material.