Fig. 3: PCM-based photonics for spaceborne applications.

a Hierarchical illustration of the applications, technologies, and sub-systems (radially outward respectively) enabled by PCM-integrated optical devices. b Three application areas are visually highlighted, (left-to-right): from miniaturized spectroscopic analysis of lunar soil [local diagnostics]; tunable photonic integrated circuit elements [data communications]; and scientifically calibrated in-flight thermal imaging of heat shields [remote sensing]. c–e Property comparison for different phase-change materials as a function of operating wavelength with major application-specific wavebands highlighted above, with: c change in refractive index (∆n = n_crys–n_amor); d extinction coefficient (∆k = k_crys–k_amor)^9,29,30; e modulation speed and maximum switching cycle (experimental)^2,5. f Visual representation of the importance of PCM performance metrics for different applications; adapted from Mikhail Y. Shalaginov et al. paper².