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Lasers
Intermediate
Stimulated emission produces coherent light.
Light Amplification by Stimulated Emission of Radiation: photons stimulate excited atoms to emit identical photons, building a coherent beam in a resonant cavity. Needs a gain medium and pumping.
He–Ne at 632.8 nm.
Not a source of 'energy from nothing'.
In more detail
A laser produces coherent, monochromatic light by stimulated emission in a gain medium placed inside a resonant cavity. Population inversion is needed for net amplification.
Real-world uses
- Lasers are used in barcode scanners, surgery, and fibre optic communication.
- Laser cutting and welding rely on high-intensity coherent light.
- Lasers power barcode scanners, fibre-optic communication, surgery and cutting tools.
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Frequently asked questions
What does laser stand for?
Light Amplification by Stimulated Emission of Radiation.
Why is the light coherent?
Stimulated emission produces photons in phase with the existing light.
What does LASER stand for?
Light Amplification by Stimulated Emission of Radiation.
Related topics in Quantum Mechanics
Quantum gates · Quantum cryptography · Quantum teleportation · Population inversion · Einstein coefficients · Blackbody and Planck's law