The Fried Parameter describes the smallest diameter of a telescope aperture at which the image fidelity starts to suffer significantly from turbulent airflows in the atmosphere of Earth.
In 1966 he joined the technical staff of the North American Aviation Science Center, Thousand Oaks, Calif., where he was engaged in a study of the microwave reflectivity and emissivity of rough surfaces.
He then designed, managed the development of the hardware for, and supervised an experiment that successfully demonstrated the validity of the laser guide-star concept.
In addition to his work related to optical propagation/turbulence effects/adaptive optics, Fried has done work in a variety of other electro-optics related fields such as the suppression of infrared background clutter in moving target detection systems; analysis of laser speckle statistics; analysis of the effect of photo-detection-event driven shot noise upon the precision of various types of optical measurements; the design and development of low-temperature-optics long-wavelength infrared sensors for use in mid course ballistic missile defense; and in the design and performance analysis for space-based infrared sensors for missile and aircraft detection.
He has also been involved in the search for a sound approach to the mid-course decoy discrimination problem for ballistic missile defense.