The interaction of light and matter has been a subject of human discovery and curiosity for over 1000 years. We have always wondered about the creation of sunlight and how it interacts with our earth and environment. Early studies of light interaction with matter were carried out using broadband light sources similar to an electric bulb. The field was, however, revolutionized by the invention of laser almost 60 years ago. Since then, lasers have seen widespread applications in almost every facet of our modern life. One key area of their usage has been as ‘sensors’ for all three primary forms of matter, namely gases, liquids and solids. Sensors are perhaps the most important and integral components of our current and future societies.
In this lecture, we will begin with a brief history of the invention of lasers. We will then describe the basic principles of how lasers (or photons) are able to interact with matter at the very fundamental level of molecules, atoms and electrons. Some introductory aspects of optics and spectroscopy will be covered. Finally, we will see how we can use lasers to develop sensors for applications in energy systems, environment monitoring and biomedical devices.
