Lecture

Laser microprocessing: beam steering and beam quality

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In course

MICRO-520: Laser microprocessing

The physical principles of laser light materials interactions are introduced with a large number of industrial application examples. Materials processing lasers are developing further and further, the lecture presents the physical limitations of the proces ...

Description

This lecture covers the fundamental concepts of laser microprocessing, focusing on beam quality, Gaussian beam parameters, Rayleigh range, depth of focus, M2 factor, and comparison between Gaussian beams and plane waves. It also discusses the importance of beam parameter product for different laser designs and the use of optical fibers in high-power laser systems.

Instructor

Patrik Willi Hoffmann

Expertise WettabilityMico-structuringElectron-beam DepositionPhotodepositionPhotoablationNano-optics Mission Patrik Hoffmann is heading the laboratory for Advanced Materials Processing at Empa. Laser materials processing including Additive Manufacturing are key topics in recent years.At the EPFL cite in the Laboratory for Optical Materials and Characterization LPMAT, novel functional material depositions by HV-CVD are studied. Recently BaTiO3 heteroepitaxial films have been grown on SrTiO3 buffered silicon

Official source

Ontological neighbourhood

Physics

Optics: Lasers

Related concepts (22)

Laser diode

A laser diode (LD, also injection laser diode or ILD, or diode laser) is a semiconductor device similar to a light-emitting diode in which a diode pumped directly with electrical current can create lasing conditions at the diode's junction. Driven by voltage, the doped p–n-transition allows for recombination of an electron with a hole. Due to the drop of the electron from a higher energy level to a lower one, radiation, in the form of an emitted photon is generated. This is spontaneous emission.

Gaussian beam

In optics, a Gaussian beam is a beam of electromagnetic radiation with high monochromaticity whose amplitude envelope in the transverse plane is given by a Gaussian function; this also implies a Gaussian intensity (irradiance) profile. This fundamental (or TEM00) transverse Gaussian mode describes the intended output of most (but not all) lasers, as such a beam can be focused into the most concentrated spot. When such a beam is refocused by a lens, the transverse phase dependence is altered; this results in a different Gaussian beam.

Fiber laser

A fiber laser (or fibre laser in Commonwealth English) is a laser in which the active gain medium is an optical fiber doped with rare-earth elements such as erbium, ytterbium, neodymium, dysprosium, praseodymium, thulium and holmium. They are related to doped fiber amplifiers, which provide light amplification without lasing. Fiber nonlinearities, such as stimulated Raman scattering or four-wave mixing can also provide gain and thus serve as gain media for a fiber laser.

Beam divergence

In electromagnetics, especially in optics, beam divergence is an angular measure of the increase in beam diameter or radius with distance from the optical aperture or antenna aperture from which the beam emerges. The term is relevant only in the "far field", away from any focus of the beam. Practically speaking, however, the far field can commence physically close to the radiating aperture, depending on aperture diameter and the operating wavelength.

Laser

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 anacronym that originated as an acronym for light amplification by stimulated emission of radiation. The first laser was built in 1960 by Theodore Maiman at Hughes Research Laboratories, based on theoretical work by Charles H. Townes and Arthur Leonard Schawlow. A laser differs from other sources of light in that it emits light that is coherent.

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