laserstråle

A laserstråle, or laser beam, is the coherent, directional light emitted by a laser. It is produced by stimulated emission of photons in a laser cavity, which amplifies light at a particular wavelength and enforces a common phase relationship among the photons. A laserstråle is typically highly monochromatic, with a well-defined direction and low divergence compared with ordinary light sources.

The main properties of a laserstråle include wavelength, power, beam quality, coherence, and polarization. The wavelength is determined by the laser medium and the resonator design. Beam quality is often described by the M2 factor, which indicates how close the beam is to an ideal Gaussian profile. Temporal coherence refers to the spectral linewidth of the emitted light, while spatial coherence describes a stable phase relationship across the beam. Polarization can be linear, circular, or elliptical, depending on the laser system and optics used.

Laserstråler come in many types, including gas lasers (for example CO2 and He-Ne), solid-state lasers (such as Nd:YAG), semiconductor diode lasers, dye lasers, and fiber lasers. The beam quality and power range vary across these types, from milliwatts in some communications applications to kilowatts in industrial cutting and welding.

In propagation, a laserstråle tends to be highly collimated, with divergence inversely related to the aperture size and wavelength. When focused by a lens, it can produce very small spot sizes, enabling precision processing or surgical procedures. Atmospheric propagation can be affected by scattering and absorption, limiting long-distance free-space use.

Applications span materials processing, medical and cosmetic procedures, communications and sensing, spectroscopy, and research. Safety is essential: laserstråler can cause eye and skin injuries, and are subject to classification and control measures to minimize risks.