Laser Beam Expander Theory

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Laser beam expander theory.

Our fixed magnification rotating lens optical beam expander. Galilean beam expanders in which an objective lens with a negative focal length and an image lens with a positive focal length are separated by the sum of their focal lengths are simple lower cost designs that also avoid the internal focus of keplerian beam expanders figure 4 the lack of an internal focus makes galilean beam expanders better suited for high power laser applications than. The fixed magnification sliding lens beam expanders are offered with optics that have either narrowband or wideband ar coatings. The first application of this theory was to evaluate the laser linewidth in multiple prism grating laser oscillators.

At minimum a beam expander design requires a specific wavelength or wavelength range a specific input beam diameter and a minimum acceptable transmission. Lasers variety of dpss diode gas or semiconductor lasers as well as laser accessories for measuring positioning bar code scanning life sciences or machine vision applications. Larger wavelength ranges are more difficult to design adding complexity and cost whereas smaller input apertures are easier over which to maintain performance requirements. Fixed magnification beam expanders are also available including achromatic and high power versions where the collimation can be fine tuned using a sliding lens adjustment mechanism and reflective beam expanders that use mirrors to expand the beam.

In a laser beam expander the placement of the objective and image lenses is reversed. Keplerian beam expanders are designed so that the collimated input beam focuses to a spot between the objective and image lenses producing a point within the system where the laser s energy is concentrated figure 3. Generally prismatic beam expanders use several prisms and are known as multiple prism beam expanders. Beam expanders are optical devices that take a collimated beam of light and expand its size or used in reverse reduce its size.

For more information on our extensive line of beam expanders please see the beam expanders tab. In laser physics they are used either as intracavity or extracavity elements. Intracavity dispersion and laser linewidth. The total intracavity angular dispersion plays an important role in the linewidth narrowing of pulsed tunable lasers through the equation where is the beam divergence and the overall intracavity angular dispersion is.

Thorlabs galilean type beam expanders which are available in both fixed and variable magnification options are offered for use in the uv visible near infrared and mid infrared spectral ranges. Questions and comments from users. Learn more about beam expander theory and design to help you get started.