  Investigating the polarization properties of light in the mid-infrared
(mid-IR) spectrum is crucial for molecular sensing, biomedical diagnostics, and
IR imaging system technologies. Traditional methods, limited by bulky size and
intricate fabrication, utilize large rotating optics for full Stokes
polarization detection, impeding miniaturization and accuracy. Van der Waals
materials (vdW) based devices can address these challenges due to their
lithography-free fabrication, ease of integration with chip-scale platforms and
room-temperature operation. This study introduces a chip-integrated polarimeter
device leveraging the in-plane biaxial hyperbolic vdW crystal properties for
mid-infrared light manipulation. The spatial division measurement scheme
incorporates six meticulously designed linear and circular polarization
filters, achieving high extinction ratios exceeding 30 dB and transmittance
surpassing 50%, with fabrication tolerance of film thickness up to 100 nm. The
proposed device represents a significant advancement in polarimetric detection,
providing a compact, cost-effective solution and opens new avenues for on-chip
mid-IR polarimetric detection in next-generation ultra-compact optical systems.
