New nanoscale dimensioning method created

GAITHERSBURG, Md., Oct. 30 (UPI) -- U.S. scientists say they've used an optical microscope to rapidly and inexpensively provide nanoscale dimensions with nanoscale measurement sensitivity.

National Institute of Standards and Technology scientists say through-focus scanning optical microscope imaging has potential applications in nanomanufacturing, semiconductor process control and biotechnology.

Institute researcher Ravikiran Attota said optical microscopes aren't usually used to check nanoscale dimensions because of the limitation imposed by light wavelength -- it's impossible to get a precise image with a probe three times the object's size.

Attota resolved the problem by considering many "bad" (out-of-focus) images. Instead of repeatedly focusing on a sample to acquire one best image, the new technique captures a series of images with an optical microscope at different focal positions and stacks them one on top of the other to create the through-focus image. A computer program Attota developed then analyzes the image.

The research was reported in the Sept. 1 issue of the journal Optics Letters.