Measurement Of Optical Filter Spectra

Accurately measuring the spectral characteristics of thin-film interference filters is crucial yet challenging, especially when dealing with steep and deep spectral edges. Standard metrology techniques often fall short, failing to capture the true blocking performance due to physical imperfections like pinholes, dirt, and mounting flaws. Commercial spectrophotometers, commonly used for this purpose, face significant limitations with high edge steepness and deep blocking filters.

This application note explores various measurement approaches employed by Semrock, highlighting the discrepancies between actual and measured spectra. By understanding these methods and their impact, users can choose the right technique to optimize filter performance, ensuring accurate results and cost-effective designs.