Step-wise tunable microbolometer long-wavelength infrared filter

This paper covers the design, fabrication, and testing of a step-wise tunable long-wavelength infrared filter. The design uses a modified type of microbolometer to filter infrared light in the 7-10 micrometer wavelength range. Fabrication of the device is accomplished using standard microelectronic and microelectromechanical systems (MEMS) fabrication techniques. Germanium and zinc sulfide are used as optical layers for good reflectivity in the desired infrared range. Testing of the device shows that it filters light in three absorption bands in the specified wavelength range. The tuning of the device is found to be step-wise in response to electrostatic actuation using voltages up to 100 volts.