Electro-Optical Characterization of SiPMs With Green Bandpass Dichroic Filters

There is an increasing interest to use silicon photomultipliers (SiPMs) in medical applications like Photoplethysmography or Functional Near Infrared Spectroscopy, allowing the monitoring of physiological signs through non-invasive equipment. The use of large area SiPMs with embedded color filters for environmental light rejection could bring relevant advantages in these applications in terms of higher signal-to-noise ratio of the measurements. Here, we report on the first electro-optical characterization results obtained on n-on-p SiPMs with green interference bandpass filters glued on the top side of the detector SMD package. We will show how the use of the filter considerably increases, especially for large overvoltage values, the SiPM dark noise rate, due to the significant amplification of optical cross-talk effects (up to 150% of dark current increase at 50%-OV). This makes necessary a careful evaluation of the SiPMs performances in order to define the best operating conditions and layout characteristics of the detectors that will be used in the final applications.