Three scientists, two American and one German, received this year’s Nobel Prize in Chemistry for circumventing a basic law of physics and enabling microscopes to peer at the tiniest structures within living cells.

The 2014 laureates, announced Wednesday by the Royal Swedish Academy of Sciences, are Eric Betzig, 54, of the Howard Hughes Medical Institute in Virginia; Stefan W. Hell, 51, of the Max Planck Institute for Biophysical Chemistry in Germany; and William E. Moerner, 61, of Stanford University in California.

For centuries, optical microscopes — those that magnify ordinary visible light — have allowed biologists to study organisms too small to be seen with the naked eye. But a fundamental law of optics known as the diffraction limit, first described in 1873, states that the resolution can never be better than half the wavelength of light being looked at.

For visible light, that limit is about 0.2 millionths of a meter, or one-127,000th of an inch. A human hair is 500 times as wide.