It is defined in milliradiant mrad, which usually describes a part of the circumcircle. The use of a 160mm focal length output lens provides the overall beam expander with magnification of 20x. Beam expanders consist of two lenses that are built according to the galileo principle and therefore do not generate an intermediate focus. Imaging a co2 laser beam passed through a beam expander. It either diverges from or converges to this beam waist. About 5% of these are lenses, 1% are laser cutting machines. Laser beam expanders are made up of an arrangement of high precision planoconcave and planoconvex lenses, and are used within a laser systems to expand or increase the size of a collimated beam. They utilise a three element design corrected for spherical abberation. Beam expander is used to modify laser beam so that the original beam waist is increased in proportion to the ratio of focal lengths of the first and second lens.
Compact beam expanders that do not sacrifice laser beam. Measure the diameter just after the beam expander and at a number of places along the beam at least a meter apart, as in question 3. Laser beam expander 650nm red laser module longrange dot position indicator40mm extender laser beam expander description. X3 beam expander the x3 mini beam expander fits perfectly on our lasers. If the beam expander is inclining, the output light will also be inclined. High cw damage threshold makes this ideal for cw laser processing applications. Beam expanders have two main purposes in the laser industry. In its simplest form, the galilean type consists of a positive and a negative focal length lens whereas the keplerian type consists of two positive focal. Generally spoken, it is best to have a divergence as small as possible. This creates a spot of concentrated energy within the beam expander which heats the air within the system and deflects light from its optical path. Laser beam expander lens, laser beam expander lens.
The focal length of the negative input lens is 8mm. The beam divergence describes the widening of the beam over the distance. It reduces beam divergence by increasing the beam diameter by three times. They are designed to be a part of the lasers without seamless, incorporating the same design language with a innovative twist. At a range of 500 meters, the kryptons beam diameter is 750mm already pretty small. Beam expanders are usually used to enlarge the laser beam diameter prior to passing through the focusing. For a diffractionlimited gaussian beam, the 1e 2 beam divergence halfangle is.
In addition to enlarging the beam diameter, beam expanders also reduce laser beam divergence. The beamexpanders are of galilean design and use multispectral zinc sulphide for the optics which has an absorbption at 1. Ruslans answer is valid because the mathematics of diffraction and of the hup are the same, as i talk about. Because a beam expander will increase the beam diameter and decrease the beam divergence by its magnifying power, we can combine these. These systems are suited for typical medium power levels of up to. In a keplerian beam expander the input beam is focussed to a point between the two lenses. Laser divergence calculator beam size over distance. Cw laser beam expanders galilean design works well for any visible or nearir laser system as a great general purpose beam expander. We shall assess how well that can be achieved with two spherical mirrors.
The purpose of a beam expander is to change the diameter and beam divergence characteristics of a laser beam passing through it. Minimal beam distortion is critical when a system is focusing to a very small spot andor beam shaping is being used to achieve a top hat flat top or donut profile. It extends the visibility range of the laser beam dramatically with the same ratio. A fixed expansion ratio beam expander typically consist of 2 lenses that comprise a simple galilean telescope. The input of each beam expander has internal sm05 0. Beam expanders are used in applications such as laser scanning, interferometry, and remote sensing. In many laser based applications, beam expanders are an essential component of the optical system. The beam divergence is in direct relation to the beam size at aperture. In this lab students will build two laserbeam expanders. This means that there is no focal length to the entire system. Made with a solid stainless steel housing, our beam expander is fully focus adjustable allowing users to control and focus the beam to where they want.
All beam expanders feature aos worldclass quality aspheric optics and precision alignment mechanics. This equation is based on the paraxial approximation, and is thus valid only for beams with moderately strong divergence a higher beam divergence for a given beam radius, i. Beam expanders are generally not designed for use with divergent beams, but only for collimated beams, and only within a certain range of beam radii. These are some of the reasons why geomatec is the largest supplier. Reflective beam expanders are modified cassegrain and gregorian mirror systems. Expander 10x adjustable focus beam expander wicked lasers. This combination produces small focused spot sizes at the work surface, with high positional accuracy and stability. The output of a laser is different than that of most other light sources. The expander works with all spyder 3 lasers, but lets take the krypton as an example. These beam expanders can be conveniently attached to most hene lasers with the 2 accessory thread and except for the t8x, are equipped with precision beam centering adjustments to compensate for slight decentrations of the entering laser beam. In such systems, the object rays, located at infinity, enter parallel to the optical axis of the internal optics and exit parallel to them as well. Build your beam expander from aos standard mount products or ask us to produce a custom product to your requirements. Every geomatec beam expander is tested for light transmission and for distortion with a beam profiling camera. Most lasers have sphericalmirror fabryperot resonators that have hermitegaussian spatial modes.
In most cases, the term is taken to mean a telescope designed to take a smalldiameter collimated beam input beam and produce a larger diameter collimated output beam, thus reducing the divergence of the beam. In size restricted applications, it is desirable to use a compact beam expander but in most cases a compact beam expander is only suitable for small diameter beams. Find details of companies offering laser beam expander at best price. It is not possible to obtain a decreased beam diameter by using the beam expander on the opposite side. This design has a slightly longer footprint and should not be used in high power laser applications unless in a. The laser resonator determines the spatial characteristics of the laser beam. When using the keplerian or galilean designs in laser beam expander applications, it is important to be able to calculate the output beam divergence. Each offaxis beam expander is housed in an aluminium housing with provision for fixing to an optical table. Why might i want a beam expander on my laser marking system. Thorlabs galilean type beam expanders, which are available in both fixed and variablemagnification options, are offered for use in the uv, visible, near infrared, and midinfrared spectral ranges. How to select the proper lens for your co2 laser and understanding laser optics duration.
Ftheta lenses made with an array of two to five optics provide a constant focal plane throughout the entire field of view, and are often. Thus beam expansion reduces the beam divergence and enables the emission of very. They are most often used to decrease divergence or to. Optical surfaces ltd laser beam expander common focus option. What is realistically the least possible beam divergence. Even a perfect unaberrated ray of light will experience some beam divergence due to di. Depending upon the accuracy of your alignment and distance available, it may be difficult to see any divergence at all. The fixedmagnification, slidinglens beam expanders are offered with optics that have either narrowband or wideband ar coatings. Beam expanders are optical devices that take a collimated beam of light and expand its size in. Our fixedmagnification, rotatinglens optical beam expander. Book depository books with free delivery worldwide. With the expander, the kryptons beam diameter is just 95mm, allowing for pinpoint targeting and a. Optical surfaces beam expanders are portable and can be used without the need for internal realignment. The term is relevant only in the far field, away from any focus of the beam.
In the design of a laser beam expander, the objective and image lenses are reversed. Both the object and the image are located at infinity, which means that the input and output beams are collimated afocal system. Beam expanders are required in most laser systems to change the diameter of the incoming source to match the requirement of the optical system. Dioptika beam expander, beam expanders, laser expander. Co2 laser beam expander can improve beam collimation characteristics. Contemporary laser beam expander designs are afocal systems that developed from wellestablished optical telescope fundamentals.
Wavefront error is caused by imperfections in the lenses and mirrors, in addition to. By increasing the beam size at the aperture it is possible to reduce the divergence. Laser beam expanders are designed to either decrease the lasers beam spot size at large distances or produce a larger diameter collimated laser beam. W4147 make sure that the beam expander is well aligned with the laser light axis. A laser beam expander is designed to increase the diameter of a collimated input beam to a larger collimated output beam. An alternative for the beam expander design is to use two offaxis paraboloids with a common focus.
Yag and yb doped fibre lasers operating near the 1. A beam expander is any optical system designed to increase the diameter of a laser beam. Divergence is the angular spreading of light waves as they propagate through space. 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. Practically speaking, however, the far field can commence physically close to the radiating aperture. Powerline avia nx uv laser subsystem for micromachining applications here the powerline avia nx is a class iv laser subsystem which mates a 40 watt avia nx laser source with a two axis galvanometer deflector, a beam expander and an ftheta scan lens. Stating that the product of beam diameter and divergence is constant for one.
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