Optical methods are non-invasive tools, and their use in sensing applications is continuously increasing and reaching new heights. Novel optical technologies contribute to the development of state-of-the-art sensing schemes and devices characterized by outstanding working parameters (very low detection limit, high specificity and sensitivity) and innovative approaches for detecting the presence of analytes and for quantitatively determining their concentrations in many fields, including pharmaceutical research, medical diagnostics, environmental monitoring, agriculture, industry, food safety, and security.

In this Special Issue, original research papers and review articles are included to display an overview of the recent advances in the technology and applications of optical sensors, including source and detection technologies, sensor architectures, sensor performance, and processing approaches and applications. This collection of papers shows the diversity of the latest developments in these areas and their wide dissemination in numerous fields.

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