  Multispectral imagers that capture spatial and spectral information are of
growing importance in various fields, particularly in remote sensing and
metrology. To enable integrated snapshot multispectral imagers and eliminate
the drawbacks of traditional systems, such as bulkiness and slow scanning
mechanisms, miniature, broadband multispectral filter arrays with narrow line
widths, high transmission, and CMOS compatibility are essential. However,
current miniature filter arrays, primarily based on diffraction nanostructures,
suffer from limitations such as small working bandwidth, low transmission, poor
color purity, and sensitivity to polarization and incident angles. To address
these challenges, we present a high-order Fabry-Perot Multispectral Filter
Array (MSFA) with selective peak suppression, leveraging subwavelength
structures for filter tuning without changing the physical thickness and
employing an ultrathin metal layer to exploit high-order resonances,
significantly extending the working range and spectral resolution. High color
purity across a broad range (400nm-1000nm) is made possible through optical
absorption from polysilicon and selective suppression from a platinum layer.
The fabricated color filter arrays cover wavelengths from 622nm to 960nm, with
Full Width Half Maximum (FWHM) ranging from 13nm to 31nm and average
transmissions exceeding 60%. Furthermore, these filters can be downscaled to
sizes compatible with modern CMOS imagers, reaching dimensions as small as 1um.
The introduction of a resonance combining design further extends the working
range (455nm-960nm), aligning with the capabilities of silicon photodetectors.
Its adaptability across wavelength ranges and potential for tunable
applications hold promise for transformative imaging and display technologies
across a wide spectrum.
