Micron-scale imaging using bulk ultrasonics.

An extraordinary resolution down to 50 microns is demonstrated for the first time for bulk ultrasonics, using novel micro-fabricated metamaterial lenses. The development and performance of the silicon-based Fabry-Perot type metalenses with an array of 10 micrometre square holes are discussed. Challenges in wave reception are addressed by a custom-developed micro-focal laser with a sub-micron spot size and an innovative experimental set-up together with physics based signal processing.

Optical monitoring of nonquarterwave film thicknesses using a turning point method.

A method is presented for monitoring film thicknesses in fabricating multilayer structures where the thicknesses are not simply quarterwave multiples. This method is similar to the conventional turning point method, except that the monitor signal wavelength is allowed to vary from one layer to the next. No physical modifications to the conventional apparatus are required.