Number 144 (Story #4), September 20, 1993 by Phillip F. Schewe and Ben Stein THE LASER FEEDBACK MICROSCOPE (LFM) achieves vertical resolutions of 10 nm, much better than for standard scanning electron microscopes (SEM). The LFM horizontal resolution, about 200 nm, is not as good as for the SEM; on the other hand, LFM can look at living cells without damaging them, unlike SEM, which operates in a vacuum. In general, microscopes illuminating targets with light usually have a resolution no finer than the light's wavelength, a fact which has ruled out optical microscopy for much biological work. The LFM overcomes this problem by forming computer-processed images from the interference of laser light going to, and reflecting from, the target via a pinhole baffle. The LFM was developed by Berkeley biophysicist Alan Bearden. (Science, 3 Sept. 1993.)