Beyond Sensitivity: A Perspective on Transitioning Photonic Sensors into Real-Life Applications.

Photonic sensing encompasses technologies at markedly different levels of maturity. Fiber-optic sensing systems are already widely deployed in infrastructure, energy, transportation, and industrial monitoring, whereas many integrated biosensors and plasmonic, metasurface, and wearable platforms remain at laboratory or early translational stages. This review critically examines the factors that have enabled some photonic sensing technologies to achieve sustained deployment while continuing to constrain others. Practical performance is considered not only in terms of the optical transducer but also through molecular recognition, sample composition, environmental cross-sensitivity, fabrication variability, optical interrogation, microfluidics, packaging, calibration, electronics, and data processing. Established, transitional, and emerging platforms are comparatively assessed across healthcare, environmental monitoring, industrial process control, structural monitoring, and security applications. Real-life readiness is evaluated through analytical validity, selectivity, reproducibility, stability, dynamic range, response time, manufacturability, usability, and total system value. An application-driven framework is proposed in which sensing architecture, recognition chemistry, sample handling, interrogation, packaging, and validation are co-designed according to the intended operating environment. The analysis shows that successful deployment depends on robust system integration, reproducible manufacturing, application-specific validation, and a clear practical advantage rather than record sensitivity or nominal detection limits alone. Future evaluations should therefore use representative samples, independently manufactured devices, realistic operating conditions, standardized reporting protocols, and comparisons with established analytical methods.