Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

HALO Takes Runner-Up in OPN Photo Contest

Tracing of green laser light in HALO
Credit: Aly Artusio-Glimpse/NIST

The High Amplification Laser pressure Optic (HALO) was developed by NIST to measure kilo-watts of laser power with best-in-class accuracy. Here, optical power is determined by measuring the force a laser beam exerts when it is reflected by the HALO’s central mirror. Thirteen smaller mirrors redirect the beam towards the central mirror, multiplying the force and reducing the measurement uncertainty. This image was captured with a green HeNe laser, traced out with a white card to show the beam path.


Created December 1, 2020, Updated December 14, 2020