Integrated optical phased array with on-chip amplification enabling programmable beam shaping.

We present an integrated optical phased array (OPA) which embeds in-line optical amplifiers and phase modulators to provide beam-forming capability with gain and beam steering in the 1465-1590 nm wavelength range. We demonstrate up to 21.5 dB net on-chip gain and up to 35.5 mW optical output power. The OPA circuit is based on an InP photonic integration platform and features the highest measured on-chip gain and output power level recorded in an active OPA (i.e., with amplification), to the best of our knowledge. Furthermore, the OPA enables the independent control of both amplitude and phase in its arms and through this we demonstrate programmable beam shaping for two cases. First, we carried out a Gaussian apodization of the power distribution profile in the OPA emitter waveguides, leading to 19.8 dB sidelobe suppression in the far-field beam, which is the highest value recorded for active OPAs, and then we demonstrated beam forming of 0th, 1st, and 2nd order 1D Hermite-Gaussian beams in free-space.

Suspended Nanochannel Resonator Arrays with Piezoresistive Sensors for High-Throughput Weighing of Nanoparticles in Solution.

As the use of nanoparticles is expanding in many industrial sectors, pharmaceuticals, cosmetics among others, flow-through characterization techniques are often required for in-line metrology. Among the parameters of interest, the concentration and mass of nanoparticles can be informative for yield, aggregates formation or even compliance with regulation. The Suspended Nanochannel Resonator (SNR) can offer mass resolution down to the attogram scale precision in a flow-through format. However, since the readout has been based on the optical lever, operating more than a single resonator at a time has been challenging. Here we present a new architecture of SNR devices with piezoresistive sensors that allows simultaneous readout from multiple resonators. To enable this architecture, we push the limits of nanofabrication to create implanted piezoresistors of nanoscale thickness (∼100 nm) and implement an algorithm for designing SNRs with dimensions optimized for maintaining attogram scale precision. Using 8-in. processing technology, we fabricate parallel array SNR devices which contain ten resonators. While maintaining a precision similar to that of the optical lever, we demonstrate a throughput of 40 000 particles per hour-an order of magnitude improvement over a single device with an analogous flow rate. Finally, we show the capability of the SNR array device for measuring polydisperse solutions of gold particles ranging from 20 to 80 nm in diameter. We envision that SNR array devices will open up new possibilities for nanoscale metrology by measuring not only synthetic but also biological nanoparticles such as exosomes and viruses.