A femtosecond laser is a pulsed laser. Femtosecond refers to the duration of the pulse. This is not the same as the frequency of the pulse. The frequency of the pulse is the number of pulses emitted by the laser in 1s. Femtosecond lasers have a much higher resolution of time than film and television equipment, and it has been calculated that this femtosecond laser has obtained the world's shortest pulses that humans can obtain in the laboratory. Through it, we can see faster and more subtle movements, such as the process of photosynthesis in green plants, the process of cell division, the movement of electrons around atoms and so on.
Concept of femtosecond: A femtosecond is a unit of time, 1 femtosecond is only one ten trillionth of a second, i.e., 1e?15 seconds or 0.001 picosecond (1 picosecond is, 1e?12 seconds). How fast is it? We know that the speed of light is 300,000 kilometers per second, or 3×10^8 m/s. And in 1 femtosecond, light can only travel 0.3 μm, which is just less than one hundredth of a hair strand.