Laser
2021 JUL 6
Preliminary >
Science and Technology > Everyday S&T > Basics
Why in news?
- Army is looking at tapping blockchain, lasers for military use.
About Laser
- “Laser” is an acronym for Light Amplification by Stimulated Emission of Radiation.
- A laser is created when the electrons in atoms in special glasses, crystals, or gases absorb energy from an electrical current or another laser and become “excited.”
- The excited electrons move from a lower-energy orbit to a higher-energy orbit around the atom’s nucleus.
- When they return to their normal or “ground” state, the electrons emit photons (particles of light).
- These photons are all at the same wavelength and are “coherent”, meaning the crests and troughs of the light waves are all in lockstep.
- In contrast, ordinary visible light comprises multiple wavelengths and is not coherent.
- Laser light is different from normal light in other ways as well.
- First, its light contains only one wavelength (one specific color). The particular wavelength of light is determined by the amount of energy released when the excited electron drops to a lower orbit.
- Second, laser light is directional. Whereas a laser generates a very tight beam, a flashlight produces light that is diffuse.
- Because laser light is coherent, it stays focused for vast distances, even to the moon and back.
- There are many applications for laser technology including the following:
- Laser Range Finding
- Information Processing (DVDs and Blu-Ray)
- Bar Code Readers
- Laser Surgery
- Holographic Imaging
- Laser Spectroscopy
- Laser Material Processing
- Cutting
- Engraving
- Drilling
- Marking
- Surface Modification
Prelims Question
Laser technology finds application in which of the following fields?
1.DVD
2.Bar Code Reader
3.Surgery
Select the correct answer using the code given below:
(a)1 and 2 only
(b)2 and 3 only
(c)1 and 3 only
(d)1,2 and 3
Answer to the Prelims Question