Optical rejection photonic structures using two spatial filters

A method of forming an integrated device comprising:

• forming a plurality of sample wells arranged on a first layer of the integrated device, wherein individual sample wells of the plurality of sample wells are configured to receive a sample configured to emit emission light in response to excitation light;
• forming a plurality of photodetectors arranged on a second layer of the integrated device and positioned to receive photons of emission light emitted from the plurality of sample wells, wherein the plurality of sample wells and the plurality of photodetectors form pixels, each of at least some of the pixels including a sample well of the plurality of sample wells aligned with at least one photodetector of the plurality of photodetectors, and a signal generated by the at least one photodetector indicates photons of emission light emitted by a sample in the sample well;
• and
• forming at least one photonic structure configured to attenuate the excitation light relative to the emission light, wherein the at least one photonic structure includes at least one spatial filter including a first spatial filter with first openings each having a first size and a second spatial filter with second openings each having a second size, wherein a first opening of the first spatial filter and a second opening of the second spatial filter overlap with a sample well, the first spatial filter is positioned between the first layer and the second spatial filter, and the first size is greater than the second size.