What is Laser: Definition and 1000 Discussions

A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. The word "laser" is an acronym for "light amplification by stimulated emission of radiation". The first laser was built in 1960 by Theodore H. Maiman at Hughes Research Laboratories, based on theoretical work by Charles Hard Townes and Arthur Leonard Schawlow.
A laser differs from other sources of light in that it emits light which is coherent. Spatial coherence allows a laser to be focused to a tight spot, enabling applications such as laser cutting and lithography. Spatial coherence also allows a laser beam to stay narrow over great distances (collimation), enabling applications such as laser pointers and lidar. Lasers can also have high temporal coherence, which allows them to emit light with a very narrow spectrum. Alternatively, temporal coherence can be used to produce ultrashort pulses of light with a broad spectrum but durations as short as a femtosecond.
Lasers are used in optical disc drives, laser printers, barcode scanners, DNA sequencing instruments, fiber-optic, semiconducting chip manufacturing (photolithography), and free-space optical communication, laser surgery and skin treatments, cutting and welding materials, military and law enforcement devices for marking targets and measuring range and speed, and in laser lighting displays for entertainment. Semiconductor lasers in the blue to near-UV have also been used in place of light-emitting diodes (LED's) to excite fluorescence as a white light source. This permits a much smaller emitting area due to the much greater radiance of a laser and avoids the droop suffered by LED's; such devices are already used in some car headlamps.

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  1. P

    Understanding laser power terminology

    I see that many LIDAR systems use power in the millijoule range in atmospheric research. A typical number is 25 millijoules. 25 millijoules is equal to 25 milliwatt/seconds. This means 25 milliwatts for one second. This seems like a tiny amount of power, yet a 25 millijoule laser costs many...
  2. P

    Combining two DC voltages for laser locking

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  3. Lord Crc

    Observation of laser pulse propagation in optical fibers

    Just wanted to share this, mainly because I really liked the videos (found in the supplementary section at the end). Moderators, feel free to move it to a more appropriate place. Observation of laser pulse propagation in optical fibers with a SPAD camera Recording processes and events that...
  4. donavi

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  5. A

    Software for laser simulations

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  6. W

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  7. Daniel Petka

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  8. Daniel Petka

    B Quantum Tunneling and Heat Distribution in Laser Cavities?

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  9. Karolus

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  10. L

    A laser emitting light with a wavelength of 560 nm (Single slit).

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  11. Q

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  12. A

    Imagine that you are conducting an activity with a laser....

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  13. J

    B Laser Pointer at Speed of Light: Does It Point Ahead?

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  14. AdrianMachin

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  15. F

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  16. G

    I Ratio between spontaneous/stimulated emission

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  17. N

    Beam Divergence from non-circular laser beam

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  18. D

    Determining hole size using laser interference

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  19. N

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  20. bluejay27

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  21. D

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  22. P

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  23. M

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  24. G

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  25. F

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  26. K

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  27. Tiny Rick

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  28. senobim

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  29. hackhard

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  30. A

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  31. A

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  32. P

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  33. E

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  34. Ivor Denham

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  35. Tareq Naushad

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  36. H

    I Is it possible to image individual air molecules?

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  37. M

    Practical scenario: NIR laser, black light marker and lamp.

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  38. whitsona

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  39. P

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  40. E

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  41. T

    Please explain this laser phenomena

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  42. Kg91

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  43. LightHero

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  44. D

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  45. C

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  46. E

    A Can we make a circular polarization laser directly?

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  47. teroenza

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  48. T

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  49. Dakota

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  50. J

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