Femtosecond laser - A laser that uses extremely short pulses of light, measured in quadrillionths (millionths of a billionth) of a second.
Photon - A particle of light.
Reflection - The change in direction experienced by light when it hits a surface or object, such as a mirror.
Scattered light - Light that is caused to deviate from its normally straight path, due to an obstacle, for example, and move in a way that is different from a simple reflection from a surface, for example a spreading out of a light beam after it hits a wall.