The mid-to-late 1960s period marks a shift toward solid-state optical sensing, emphasizing integrated detector arrays, high-sensitivity photodetectors, and infrared materials. Research clusters around monolithic sensor mosaics, wide-bandwidth photodetectors, and pyroelectric infrared detectors, coupled with spectral sensing techniques to enable compact, robust imaging and spectroscopy. Historical Significance: These advances cement the paradigm of integrated solid-state optical sensing as the backbone for modern imaging sensors, infrared detectors, and chemically/spectrally resolved sensing, paving the way for widespread application in imaging, communication, and environmental monitoring.