A femtosecond is a unit of time equal to one quadrillionth of a second, or 10^-15 seconds. It is often used in fields like physics and chemistry to measure extremely fast processes, such as the movement of electrons in atoms or the duration of laser pulses. In the realm of laser technology, femtosecond lasers can produce incredibly short bursts of light, allowing scientists to capture rapid events that occur on the atomic scale. This capability has applications in medical imaging, material processing, and spectroscopy, enabling advancements in both research and industry.