Fig. 4.

Components and results from DF-IR imaging. (A) Schematic of a designed filter. (B) Characterization of the designed filter by microscopy and atomic force microscopy shows the ability to fabricate structures as per design and their uniformity. (C) The imperfect prediction and fabrication capabilities at this early stage, however, do present challenges in translating the narrowband predicted performance (for example, on the left) to actual filter performance (right). (D) Tens of filters can be placed on a single substrate and fabricated together on the same optical path using the concept of a filter wheel. (E) Schematic of setup for characterization of the filter, spectroscopy or for comparison with FT-IR imaging. (F) An absorbance image from an unoptimized system showing the antisymmetric CH stretching band absorbance of an SU-8 sample. The image size is approximately 500 μm × 500 μm. White levels indicate a higher beam attenuation and gray/black levels indicate little to no attenuation.