Picosecond

A picosecond (abbreviated as ps) is a unit of time in the International System of Units (SI) equal to 10⁻¹² or 1⁄1 000 000 000 000 (one trillionth) of a second. That is one trillionth, or one millionth of one millionth of a second, or 0.000 000 000 001 seconds.

picosecond
Unit system	SI
Unit of	time
Symbol	ps
Conversions
1 ps in ...	... is equal to ...
SI units	10−12 s

A picosecond is to one second, as one second is to approximately 31,688.76 years.

Multiple technical approaches achieve imaging within single-digit picoseconds: for example, the streak camera or intensified CCD (ICCD) cameras are able to picture the motion of light.^[1][2]

One picosecond is equal to 1000 femtoseconds, or 1/1000 nanoseconds. Because the next SI unit is 1000 times larger, measurements of 10⁻¹¹ and 10⁻¹⁰ second are typically expressed as tens or hundreds of picoseconds. Some notable measurements in this range include:

• 1.0 picoseconds (1.0 ps) – cycle time for electromagnetic frequency 1 terahertz (THz) (1 x 10¹² hertz), an inverse unit. This corresponds to a wavelength of 0.3 mm, as can be calculated by multiplying 1 ps by the speed of light (approximately 3 x 10⁸ m/s) to determine the distance traveled. 1 THz is in the far infrared.
• 1 picosecond – time taken by light in vacuum to travel approximately 0.30 mm
• 1 picosecond – half-life of a bottom quark
• ~1 picosecond – lifetime of a single H
  ₃O⁺
  (hydronium) ion in water at 20 °C^[3]
• picoseconds to nanoseconds – phenomena observable by dielectric spectroscopy
• 1.2 picoseconds – switching time of the world's fastest transistor (845 GHz, as of 2006)^[4]
• 1.7 picoseconds – rotational correlation time of water^[5]
• 3.3 picoseconds (approximately) – time taken for light to travel 1 millimeter
• 10 picoseconds after the Big Bang – electromagnetism separates from the other fundamental forces
• 34 picoseconds – signal rise time (20% to 80%) of a SFP+ transmitter for 10 Gigabit Ethernet.^[6]
• 10–150 picoseconds – rotational correlation times of a molecule (184 g/mol) from hot to frozen water^[7]
• 100 picoseconds – Unit Interval of a 10 Gbps serial communication link, such as USB 3.1.^[8]
• 108.7827757 picoseconds – transition time between the two hyperfine levels of the ground state of the caesium-133 atom at absolute zero
• 330 picoseconds (approximately) – the time it takes a common 3.0 GHz computer CPU to complete a processing cycle

See also

• SI unit
• Second
• Nanosecond
• Microsecond
• Millisecond
• Jiffy (time)
• Orders of magnitude (time)

References

1. "Trillion-frame-per-second video". Massachusetts Institute of Technology. Retrieved 2014-03-06.
2. "Ultra high speed CCD cameras capture the motion of light". Stanford Computer Optics. Retrieved 2014-03-06.
3. "Lifetime of single hydronium (H3O+) ion at 20°C". BioNumbers. Retrieved 2011-10-10.
4. James E. Kloeppel (2006-12-11). "World's Fastest Transistor Approaches Goal of Terahertz Device".
5. Lankhorst, D.; Schriever, J.; Leyte, J. C. (1982). "Determination of the Rotational Correlation Time of Water by Proton NMR Relaxation in H217O and Some Related Results". Berichte der Bunsengesellschaft für physikalische Chemie. 86 (3): 215–221. doi:10.1002/bbpc.19820860308.
6. SFF Committee. "SFF-8431 Specifications for Enhanced Small Form Factor Pluggable Module SFP+" (PDF).
7. Bulla, I.; Törmälä, P.; Lindberg, J. J.; Mikalsen, Ø.; Southern, J. T.; Edlund, K.; Eliasen, M.; Herskind, C.; Laursen, T.; Pedersen, P. M. L. (1975). "Spin Probe Studies on the Dynamic Structure of Dimethyl Sulfoxide-Water Mixtures". Acta Chemica Scandinavica. 29a: 89–92. doi:10.3891/acta.chem.scand.29a-0089.
8. "Universal Serial Bus 3.1 Specification" (PDF).

External links

• National Institute for Standards and Technology Glossary