Smooth superlens images at 1/12 wave resolution

March 1, 2010
With a negative refractive index, a planar slab "superlens" can image features below the diffraction limit by recovering evanescent waves as well as ordinary free-space light waves.

With a negative refractive index, a planar slab "superlens" can image features below the diffraction limit by recovering evanescent waves as well as ordinary free-space light waves. One approach to building such a device is to use a film of silver (Ag), which although it does not have a negative index, has a negative permittivity, which is sufficient to act on light with a transverse magnetic polarization. However, when fabricated as a thin enough film, Ag normally forms islands, resulting in a roughness high enough to interfere with the superlensing effect.

But by depositing a film of germanium (Ge) between a 15 nm layer of Ag and the chromium (Cr) sublayer, researchers at the University of Illinois (Urbana, IL), Hewlett-Packard Laboratories (Palo Alto, CA), and the University of California (Davis, CA) have made a superlens smooth enough (with a subnanometer roughness) capable of resolving at 1/12 the illumination wavelength. The object to be imaged was a grating in the Cr layer with a 30 nm half-pitch. At an incident wavelength of 380 nm, the grating was imaged at 1:1 into photoresist with high fidelity. A corrugated silver surface could be added to enable far-field imaging, say the researchers. Contact Nicholas Fang at [email protected].

Sponsored Recommendations

March 31, 2025
Enhance your remote sensing capabilities with Chroma's precision-engineered optical filters, designed for applications such as environmental monitoring, geospatial mapping, and...
March 31, 2025
Designed for compatibility with a wide range of systems, Chroma's UV filters are engineered to feature high transmission, superior out-of-band blocking, steep edge transitions...
March 31, 2025
Discover strategies to balance component performance and system design, reducing development time and costs while maximizing efficiency.
March 31, 2025
Explore the essential role of optical filters in enhancing Raman spectroscopy measurements including the various filter types and their applications in improving signal-to-noise...

Voice your opinion!

To join the conversation, and become an exclusive member of Laser Focus World, create an account today!