  Programmable and reconfigurable optics hold significant potential for
transforming a broad spectrum of applications, spanning space explorations to
biomedical imaging, gas sensing, and optical cloaking. The ability to adjust
the optical properties of components like filters, lenses, and beam steering
devices could result in dramatic reductions in size, weight, and power
consumption in future optoelectronic devices. Among the potential candidates
for reconfigurable optics, chalcogenide-based phase change materials (PCMs)
offer great promise due to their non-volatile and analogue switching
characteristics. Although PCM have found widespread use in electronic data
storage, these memory devices are deeply sub-micron-sized. To incorporate phase
change materials into free-space optical components, it is essential to scale
them up to beyond several hundreds of microns while maintaining reliable
switching characteristics. This study demonstrated a non-mechanical,
non-volatile transmissive filter based on low-loss PCMs with a 200 $\mu$m$
\times $200 $\mu$m switching area. The device/metafilter can be consistently
switched between low- and high-transmission states using electrical pulses with
a switching contrast ratio of 5.5 dB. The device was reversibly switched for
1250 cycles before accelerated degradation took place. The work represents an
important step toward realizing free-space reconfigurable optics based on PCMs.
