Temperature-stable LED-based light source without temperature control

Abstract

Many medical, environmental, and industrial sensing applications could take advantage of uncooled temperature-stable optical sources that are incoherent and un-polarized as such sources do not produce interference fringes, speckle patterns, or intensity variations due to polarization. For this purpose we propose an optical system for stabilization of light-emitting diodes over temperature exhibiting output power variation below 50 ppm/°C which does not employ any kind of TEC elements or even thermometers. This makes it especially suitable for handheld and battery operated instruments.