Lasers outperform LEDs for therapy because laser light is coherent, monochromatic, and has controlled divergence, so it delivers roughly 90% of its energy into tissue versus just 1 to 20% for LEDs. Meanwhile, laser diodes emit focused light with a narrow beam. What's an LED? Light-emitting diode, also known as an LED, is a semiconductor. LED and laser are both semiconductor devices that interact with light energy and electricity but function differently. LED focuses on efficient, broad illumination while laser light delivers concentrated precision. They are used in laser pointers and specialized scientific and industrial applications (optical pumping of other lasers, spectroscopy, surface hardening, welding).