What is a laser?
The full form of ‘laser’ is actually ‘Light Amplification by Stimulated Emission of Radiation’. Did you know that we use lasers every single day? We use laser printers in offices, lasers to scan the barcodes on products when we buy them and doctors use lasers in life-saving surgeries! But have you ever stopped to wonder exactly what a laser is and how it works? The light that we see around us is a mixture of beams at different wavelengths. Together they can be seen as ‘White Light‘, which is colourless. Lasers, unlike natural light, do not occur in nature and are a creation of man. Scientists figured out how to artificially create this special kind of light.
How can laser light cut through solid objects?
A laser cannot be simply defined as a very strong torch. Lasers produce a narrow, intense beam of light, which is strengthened using a curved mirror. Unlike the light we see around us, the light from a laser consists of rays which are all at the same wavelength. Owing to this property, the waves of light in a laser travel in phase (with their peaks lined up). It is able to cut through things because of this intensity and the fact that it can be focussed into a very tiny spot. It is different from a simple beam of light in many ways. A laser is ‘monochromatic’- only of one colour. This is because all the light in a laser beam is of the same wavelength. The rays of light in a laser are also ‘collimated’ – they can travel in beams parallel to each other, which allows them to travel in a straight beam for long distances. Lastly, the light is ‘coherent’, meaning that it moves in phase together.