Spatial Characterization of LED's Irradiance using Ordinary Detectors

A. Raghu, T. Shivalingaswamy and P. E. Rashmi

Post Graduate Department of Physics, Government College (Autonomous), Mandya 571401, India.

In this article, irradiance profiles of common LEDs along the beam propagation direction and in a plane perpendicular to propagation direction are studied using inexpensive photo detectors, viz., photo diode and photo transistor. Different methods used in Indian institutes for the analysis of radiation are discussed along with their limitations and advantages. General considerations required to characterize anisotropic radiators using ordinary detectors are discussed. It is found that, out of the two detectors photo transistor works better for LED’s radiations. These results are compared with results obtained from another anisotropic radiator, viz., open laser diode and one isotropic radiator incandescent lamp.