Investigation of Enviromental Effects on the Normalized Spectral Responsivity of an InGaAs Detector

Medical and clinical use of single element photodetectors and two-dimensional arrays based on InGaAs material and its derivatives have increased significantly in the last two decades. Especially, medical instrumentations and applications utilizing Raman spectroscopy in the Near Infrared (NIR) Region of electromagnetic spectrum are among the promising methods in the field. In this work we describe the impact of ambient temperature effects on the spectral sensitivity of a single element InGaAs detector. For this purpose the normalized spectral responsivity of an InGaAs photodiode was examined at different controlled environmental conditions. Particularly, the normalized spectral responsivities were recorded at different ambient temperatures ranging from +10 degrees C to +40 degrees C at various environmental humidity values and analyzed. The measurements were performed twice, with and without the external electronic circuit for cooling of the active element of the detector, and then compared. It was found that when used in the properly cooled conditions the spectral sensitivity of the InGaAs detector demonstrates a stable behaviour.