Optical techniques involve the use of light to analyze and manipulate materials. These methods can include microscopy, where light is used to magnify small objects, and spectroscopy, which analyzes the interaction of light with matter to determine chemical composition. These techniques are widely used in various fields, including biology, chemistry, and materials science. They help scientists and researchers visualize structures, identify substances, and study properties at the microscopic level, making them essential tools in both research and industry.