A tunable optical filter for a detector is presented including a plate having a top side and a bottom side. The plate has material properties making it transparent to a range of optical frequencies. A transparent metasurface is proximate the top side of the plate. The transparent metasurface is configured to have a transmissive pass band and a stop band. An undercarriage support structure is proximate the bottom side of the plate. The undercarriage support is responsive to photothermal heating. The undercarriage support is configured to deform from the photothermal heating caused by an undesired signal thereby shifting the stop band in frequency toward the undesired signal to block reception of the undesired signal by the detector.