Abstract

The parametric photometer is a device for the absolute measurement of the radiation spectral brightness by means of parametric down-conversion.¹ The principal block-scheme of such a device is presented in Fig. 1. The beam of the radiation under measurement from one side and the beam of the laser pump source from the other side are directed to the nonlinear crystal at the proper angles for parametric down-conversion. At the entrance of the crystal converter the signal radiation of shifted frequency is recorded by a detector. The registrated radiation frequency ω₁ is determined by the frequency ω₂ of the radiation being measured and pump frequency ω₀ by the relation ω₀ = ω₁ + ω₂.

© 1994 IEEE