Lasers
Lasers operate based on interactions of matter and light, primarily through the mechanisms of absorption, spontaneous emission, and stimulated emission, with stimulated emission being fundamental for laser operation. A critical condition for lasing is population inversion, where more atoms are in an excited state than in the ground state, allowing for amplified light through stimulated emission. Different types of lasers include gas, solid-state, and dye lasers, each having unique properties and applications. Laser beams share distinctive qualities such as monochromaticity, coherence, directionality, and exceptional brightness, leading to a myriad of uses in science, engineering, and medicine.
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What we have learnt
- Stimulated emission is crucial for producing coherent light.
- Population inversion (N2 > N1) is necessary for effective lasing.
- Lasers can be categorized into gas, solid-state, and dye types, each with unique operational principles and applications.
- Laser beams possess properties like monochromaticity, coherence, directionality, and high brightness.
- Applications of lasers span multiple fields including holography in science, metal cutting in engineering, and laser surgeries in medicine.
Key Concepts
- -- Stimulated Emission
- The process by which an incoming photon induces an excited atom to drop to a lower energy state, emitting a second identical photon.
- -- Population Inversion
- A condition in which a greater number of atoms are in an excited state than in the ground state, essential for the generation of a laser.
- -- Monochromaticity
- The quality of laser light to have a single wavelength, resulting in a very narrow spectral width.
- -- Coherence
- The property of laser light where all photons are in phase, both temporally and spatially.
- -- Laser Beam Properties
- Includes the high intensity, narrow beam divergence, and higher brightness compared to conventional light sources.
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