Near-infrared light is a type of light that is invisible to our eyes, but not to some machines. It's like a special type of light that can get through certain things - like our skin. Near-infrared light has special properties that make it helpful for doctors and scientists to see things in our bodies that we can't see with our eyes.
When near-infrared light is shined on our skin, it passes through our skin and into our tissue. This is called the 'near-infrared window'. Some of the near-infrared light is reflected back, out of our skin. Special machines can pick up this reflected near-infrared light and use it to create a picture of what's going on inside our bodies, like our organs and bones. This helps doctors and scientists understand what might be happening inside our bodie so they can help us stay healthy.