Irradiance measurements without explicit diffraction corrections

• Published in: Metrologia Vol. 40; no. 1; pp. S189 - S191
• Main Authors: Suarez-Romero, J G, Tepichín-Rodríguez, E
• Format: Journal Article
• Language: English
• Published: IOP Publishing 01.02.2003
• ISSN: 0026-1394
• DOI: 10.1088/0026-1394/40/1/343

Absolute irradiance (and radiance) measurements are normally carried out with a radiometric bench consisting of two field apertures and a photodetector. Irradiance measurements are taken considering rectilinear propagation and are normally corrected from diffraction effects. In this work we treat irradiance measurements considering wave propagation and calculating the double diffraction. Within our proposal, the effects of diffraction, typically referred to as diffraction corrections, are handled naturally in the propagation of the cross-spectral density. This wave propagation allows us to calculate an instrument constant of the optical system, which for this case can be treated as a constant correction in irradiance as a function of distance. We show experimental results that verify our proposal.