Dispersion frequency
A dispersion frequency was an adjustable setting to Starfleet hand phasers in the 24th century.

In 2373, when Voth scientists Gegen and Veer used interphase technology to infiltrate the  in order to conduct archaeological research, their presence was given away when the crew detected spatial fluctuations with a highly-localized modulating phase variance. The crew eventually determined that a hand phaser adjusted to a dispersion frequency of 1.85 gigahertz would disrupt their interphase, and Gegen and Veer were discovered. ()

See also
Frequency

Directed energy weapons