Synchronous micromechanically resonant programmable photonic circuits.

Programmable photonic integrated circuits (PICs) are emerging as powerful tools for control of light, with applications in quantum information processing, optical range finding, and artificial intelligence. Low-power implementations of these PICs involve micromechanical structures driven capacitively or piezoelectrically but are often limited in modulation bandwidth by mechanical resonances and high operating voltages. Here we introduce a synchronous, micromechanically resonant design architecture for programmable PICs and a proof-of-principle 1×8 photonic switch using piezoelectric optical phase shifters.

Optical Tunability and Characterization of Mg-Al, Mg-Ti, and Mg-Ni Alloy Hydrides for Dynamic Color Switching Devices.

Mg shows great potential as a metal hydride for switchable optical response and hydrogen detection due to its ability to stably incorporate significant amounts of hydrogen into its lattice. However, this thermodynamic stability makes hydrogen removal difficult. By alloying Mg with secondary elements, the hydrogenation kinetics can be increased.

Highly switchable absorption in a metal hydride device using a near-zero-index substrate.

Optical switchability is an important functionality for photonic devices, which allows them to accommodate a wide range of applications. One way to achieve this switchability is to utilize the reversible and tunable optical changes of metal hydrides. When exposed to H gas, certain metals go through dramatic changes in optical properties as hydrogen atoms expand the lattice spacing.

Control of hot-carrier relaxation time in Au-Ag thin films through alloying.

The plasmon resonance of a structure is primarily dictated by its optical properties and geometry, which can be modified to enable hot-carrier photodetectors with superior performance. Recently, metal alloys have played a prominent role in tuning the resonance of plasmonic structures through chemical composition engineering. However, it has been unclear how alloying modifies the time dynamics of the generated hot-carriers.

In Situ Optical and Stress Characterization of Alloyed PdAu Hydrides.

PdAu alloys have recently shown great promise for next-generation optical hydrogen sensors due to their increased chemical durability while their optical sensitivity to small amounts of hydrogen gas is maintained. However, the correlation between chemical composition and the dynamic optical behavior upon hydrogenation/dehydrogenation is currently not well understood. A complete understanding of this relation is necessary to optimize future sensors and nanophotonic devices.

Measurement of the Casimir torque.

Intermolecular forces are pervasive in nature and give rise to various phenomena including surface wetting, adhesive forces in biology, and the Casimir effect, which causes two charge-neutral, metal objects in vacuum to attract each other. These interactions are the result of quantum fluctuations of electromagnetic waves and the boundary conditions imposed by the interacting materials. When the materials are optically anisotropic, different polarizations of light experience different refractive indices and a torque is expected to occur that causes the materials to rotate to a position of minimum energy.

Apparatus for combined nanoscale gravimetric, stress, and thermal measurements.

We present an apparatus that allows for the simultaneous measurement of mass change, heat evolution, and stress of thin film samples deposited on quartz crystal microbalances (QCMs). We show device operation at 24.85 ± 0.