Scientists have invented a new design of a new thumb-sized microscope that operates something like a CD-player, using microwaves instead of visible light.  This minute but high power microscope is referred to as a Scanning Evanescent Microwave Probe or SEMP.  This high power microscope is a unique new apparatus that can be utilized to simultaneously characterize critical electronic properties along with topography in a wide variety of materials.
The SEMP is described to use near-field or non-propagating microwaves   to calculate the electrical impedance of materials with sub-micron resolution. In the electronics industry, a material’s electrical impedance means a measurement of its ability to conduct an alternating current which is considered as its most critical property.

This high power microscope has the capability of mapping the complicated electrical impedance of any material.  Scientists have chosen the lower range microwave frequencies of a few Gigahertz because it is known to be the most relevant and best-suited range for majority of electronic use.
By simply measuring the interaction between evanescent microwaves generated off an ultra sharp-tipped probe and the surface of a material, scientists   can   chart electrical impedance across the face of the material and at the same time diagram the topography of the material’s surface.  This is another significant aspect in the manufacture of chips and other electronic devices.

The Scanning Evanescent Microwave Probe sharp-tipped metal probe is linked to a high quality-factor or Q microwave resonator set with a thin-metal shield which is specifically patterned to screen out all but the evanescent microwaves from being generated at the SEMP’s tip. The result showed that when the tip is scanned above the surface of the sample, only the evanescent microwaves with their high spatial resolving power are free to interact with the sample.
This special feature is important for high resolution quantitative microscopy.  When both evanescent and propagating microwaves had to be used and calculated, like in the case for all other types of microwave probes, the quantitative microscopy would be hard to achieve.  The interface between the evanescent microwaves and the sample surface gives rise to a resonant frequency as well as quality-factor changes in the resonator that is recorded as signals.  Scientists can measure the change signals and plug the measurements into equations   which can translate the outcomes into a measurement of the sample’s complex electrical impedance with a spatial resolution of 100 nanometers.

The SEMP can be employed on conductors, insulators as well as semiconductors. It can be applied in any situation which warrants the need to characterize the electrical properties of as a role of electric or magnetic fields, optical illumination, or temperature variations. The   researchers have utilized the tip-to-sample distance feedback control techniques to get the topographical and electrical measurements of sample surfaces known to be important for mapping electrical impedance without contacting the sample surface.

Inasmuch as the feedback control varies  from nanometers to microns, SEMP as a high power microscope has a  zoom-out feature which permits it to scan a big area in a short span of time  It also has    a zoom-in feature making it possible  to scan a small area with high resolution.  With these capabilities this microscope can be considered as a practical device for industrial applications.
Scientists are working on the SEMP to further refine and expand this high power microscope.  They are trying to construct a low-temperature version which will enable them to study extensively the superconductors.