Light has long been used as a powerful tool to observe, measure and understand the world around us. From the first optical instruments to modern photonic technologies, optical sensors have evolved into highly sensitive, versatile and increasingly accessible platforms for detecting physical, chemical and biological parameters.

This talk will present a broad journey through the history and evolution of optical sensing, highlighting how light-based technologies have moved from classical laboratory instruments to compact, integrated and connected systems. The talk will include examples of sensors measured using smartphones, where the camera, screen and processing capabilities of mobile devices can be used for low-cost and portable detection. It will also address optical fibre sensors, which enable robust, remote and distributed monitoring in areas such as infrastructure, environment, energy and health.

In terms of application, several examples will be presented, focusing on civil engineering, chemical engineering, aerospace, and human factors, among others.

Finally, the presentation will introduce emerging concepts in quantum sensing, showing how quantum properties of light and matter can open new possibilities for ultra-sensitive measurements.