Microjoules

Microjoule (symbol μJ) is an energy unit in the International System of Units (SI). It equals one millionth of a joule, written as 1 μJ = 10^-6 J. In practical terms, this prefixes the joule to describe small energy quantities. Related units are 1 μJ = 0.001 mJ and 1 J = 1,000,000 μJ, as well as 1 μJ = 1,000 nJ.

Microjoules are commonly used in fields where small energy changes or deposits are relevant. This includes microfabrication and microelectromechanical systems (MEMS), where individual events or pulses may release energies in the μJ range. In optics, laser pulse energies are sometimes specified in μJ, especially for tabletop experiments or compact systems. In biology, chemistry, and calorimetry, μJ scales appear when working with very small samples or precise energy measurements.

Measurement of energies in the microjoule range typically relies on high-sensitivity instruments. Calorimeters capable of resolving microjoules, integrated energy meters for laser pulses, and photodiode-based detectors with time integration are examples of equipment used to quantify μJ-scale energies.

Summary: the microjoule is a convenient unit for describing small, lab-scale energy quantities that are too large for nan joules but too small for millijoules, fitting a wide range of experimental and engineering contexts. See also joule, millijoule, and nanojoule.