Ultrashort

Ultrashort is a term used to describe events, signals, or durations that are extremely brief. In scientific contexts it typically denotes time scales on the order of femtoseconds (10^-15 seconds) or shorter, and in everyday language it can simply mean “very brief.” The term is used across disciplines to emphasize precision about short time intervals rather than to specify a fixed value.

In ultrafast optics, ultrashort pulses are generated by mode-locked lasers and can range from tens of femtoseconds down to attoseconds. These pulses enable time-resolved measurements of fast physical, chemical, and biological processes. Characterization techniques such as frequency-resolved optical gating (FROG) and autocorrelation are used to measure pulse duration, while chirped-pulse amplification helps prevent damage when boosting peak power for practical applications.

In film and media, ultrashort refers to micro- or short-length works, typically under several minutes and often much shorter. Such pieces are common in experimental cinema, online platforms, and festival lineups, where rapid storytelling or exploration of ideas is central.

In finance, ultrashort describes investment products or strategies designed to deliver very short-duration exposure, such as ultrashort bonds or ultrashort equity funds, including leveraged or inverse variants. These instruments are used for hedging, tactical positioning, or liquidity management but carry higher risk and costs relative to longer-term investments.