Circuit elements for opto frequencies

Researchers at the University of Pennsylvania propose to shrink circuits to save space and power and, more importantly, accommodate electronic applications at much higher frequencies than are possible with current models - applications that include nano-optics, optical information storage and molecular signalling.

Electric circuit elements, among them resistors, capacitors and inductors, come in a variety of sizes to deal with a variety of applications at a range of frequencies.

The familiar electrical grid, for example, operates at a frequency of 50 Hz. A circuit designed to process radio signals operates at the 100 MHz range.

A typical frequency domain for computers is 1 GHz. Higher still, microwave applications often operate at the 10 GHz level. Higher still, microwave applications often operate at the 10 GHz level.

Na der Engheta and his Penn group would like to extend the circuit concepts up to optical frequencies.

To do this, instead of just shrinking the classic circuit elements to a fraction of the typical wavelength of the optical signal being processed (around 500 nm), the Penn proposal is to make nano-inductors, nano-capacitors and nano-resistors out of sub-wavelength nano-particles, fashioned from appropriate materials on a substrate with lithographic techniques.

Possible applications would include direct processing of optical signals with nano-antennas, nano-circuit-filters, nano-waveguides, nano-resonators and even nano-scaled negative-index optical structures.