| femtosecond | |
|---|---|
| Unit system | SI |
| Unit of | time |
| Symbol | fs |
| Conversions | |
| 1 fsin ... | ... is equal to ... |
| SI units | 10−15 s |
Afemtosecond is a unit of time in theInternational System of Units (SI) equal to 10−15 or1⁄1 000 000 000 000 000 of asecond; that is, one quadrillionth, or one millionth of one billionth, of a second.[1]
A femtosecond is to a second, as a second is to approximately 31.69 million years.
For context, a ray of light travels approximately 0.3 μm (micrometers) in 1 femtosecond, a distance comparable to the diameter of avirus.[2] The first to make femtosecond measurements was the Egyptian Nobel LaureateAhmed Zewail, for which he was awarded theNobel Prize in Chemistry in 1999. Professor Zewail used lasers to measure the movement of particles at the femtosecond scale, thereby allowing chemical reactions to be observed for the first time.
The wordfemtosecond is formed by theSI prefixfemto and theSI unitsecond. Its symbol isfs.[3]
A femtosecond is equal to 1000attoseconds, or 1/1000picosecond. Because the next higher SI unit is 1000 times larger, times of 10−14 and 10−13 seconds are typically expressed as tens or hundreds of femtoseconds.
| Color | Wavelength interval | Cycle time interval | |
|---|---|---|---|
| Red | ~ 700–635 nm | ~ 2.3–2.1 fs | |
| Orange | ~ 635–590 nm | ~ 2.1-2.0 fs | |
| Yellow | ~ 590–560 nm | ~ 2.0–1.9 fs | |
| Green | ~ 560–520 nm | ~ 1.9–1.7 fs | |
| Cyan | ~ 520–490 nm | ~ 1.7–1.6 fs | |
| Blue | ~ 490–450 nm | ~ 1.6–1.5 fs | |
| Violet | ~ 450–400 nm | ~ 1.5–1.3 fs | |