Spectral irradiance data is shown below for our Quartz Tungsten Halogen Lamps. You can click on the curve for a larger image, or on a model number for complete information on a specific QTH lamp. Spectral irradiance curves for other types of lamps can be found on the right. View Information on Spectral Irradiance Data and Using the Spectral Irradiance Curves for complete information on how the data was obtained and how to use it.