Reconstructing light wavelength spectrum with thin-film device

A method of forming a spectrometer device, the method comprising:

• predefining a plurality of filter stacks, wherein each filter stack comprises a plurality of dielectric films, each dielectric film of the plurality of dielectric films having a corresponding initial film thicknesses;
• updating a film thickness of each dielectric film of each filter stack in a spectrometer model, wherein the spectrometer model comprises the plurality of filter stacks arranged into a first filter layer and a second filter layer on the first filter layer,
• wherein each filter stack within the second filter layer is aligned with a corresponding filter stack in the first filter to define respective channels;
• and
• fabricating the spectrometer device according to the spectrometer model comprising the updated dielectric film thicknesses, wherein fabricating the spectrometer device comprises:
• providing a substrate comprising a plurality of light detector elements arranged in an array on the substrate;
• forming the first filter layer on the substrate;
• and
• forming the second filter layer above the first filter layer,
• wherein each filter stack in the second filter layer is aligned with both a corresponding filter stack in the first filter layer and a corresponding light detector element to define a respective photodetector channel, and
• wherein each photodetector channel is configured to have a different optical transmission spectrum,
• wherein forming the first filter layer comprises:
• forming a plurality of adjacent first filter stacks, each first filter stack consisting of the same structure;
• and
• after forming the plurality of adjacent first filter stacks, forming a plurality of adjacent second filter stacks, each second filter stack consisting of the same structure as each other second filter stack and comprising a different structure from the plurality of the adjacent first filter stacks,
• wherein each of the plurality of filter stacks in the first filter layer comprises a same first plurality of different filter stacks,
• wherein each of the plurality of filter stacks in the second filter layer comprises a same second plurality of different filter stacks,
• wherein each filter stack within the first plurality of different filter stacks has different dielectric film thicknesses from the other filter stacks within the first plurality of different filter stacks and each filter stack within the first plurality of different filter stacks is arranged horizontally to form a portion of the first filter layer, and
• wherein each filter stack within the second plurality of different filter stacks has different dielectric film thicknesses from the other filter stacks within the second plurality of different filter stacks and each filter stack within the second plurality of different filter stacks is arranged horizontally to form a portion of the second filter layer.