It’s not always easy to imagine how short space of time a femtosecond occupies, when a blink of our eyes takes 1011 times longer. Here’s how we can approach to this unusual unit by a simple math.
A femtosecond is 10-15 second or a quadrillionth of a second. We use femtosecond pulse lasers to study femtosecond phenomena -- such as electronic excitation and phononic oscillations --- in solid materials.
There’s a trick to easily grasp how short a femtosecond is. You know in astronomy ultralarge distances are described in the unit of “light year”. One light year is the distance light travels in the time span of one year, and is roughly 9.461 quadrillion km in our daily unit.
We can consider the other way round to express ultrashort time. For example, in one millionth of a second light travels 300 m; we can call 1 microsecond as 300 “light meters”. One femtosecond is 0.3 “light micrometers”, which is roughly the size of a virus !!
Logarithmic plot to convert ultrashort time into reasonable distance, as well as ultralarge distance into reasonable span of time.
