The purpose of the bookmarks for the project Photonics4All is to increase the public awareness of photonics and especially of the technological advances of photonics which have changed and improved everyday life (basic technology introduction). How can light replace a needle? We no longer need to use a needle to monitor the level of oxygen in your blood! We can use light emitting diodes (LEDs) attached to the top of your finger - and a light detector underneath to measure the amount of light passing through your finger. As Hemoglobin - the proteins in red blood cells which carry oxygen - absorbs light we can determine whether you have enough oxygen in your blood. More advanced devices can also monitor your heart-rate and blood pressure. We'll even be using light to measure your blood-sugar level in the future. All thanks to Photonics! ...