While many lasers will output a Gaussian mode, this is not always the most desirable beam profile for a particular application. As we have seen, Gaussian beams have an M2 = 1 and consequently have a low divergence for a given waist size; this makes them suitable for applications where the laser beam must travel a long distance and still maintain some degree of energy concentration. Gaussian beams are also easy to understand in terms of their propagation since they remain invariant in shape, only changing in size following simple analytical rules (see Chapter 1). However, in many applications a flat-top beam profile, sometimes called a top-hat beam, would be more advantageous, for example, in materials processing, lithography, micromachining, and medical applications. In many of these applications, a beamwith a near uniform distribution of energy is desirable: while a Gaussian beam would have a peak energy density of double the average, a flat-top beam would ideally have the same energy density across the entire active area of the beam. In Via drilling this would mean a drill rate that is the same across the area of the hole. In medical applications, say eye surgery, it would mean that the rate of material removal would be equal across the beam and would avoid potential damage due to the large peak energy density at the center of a Gaussian beam. Unfortunately, flat-top beams suffer from some disadvantages: they are not part of the mode set of standard laser resonators and so require custom optics either inside or outside the laser in order to create them; they do not propagate in a shape invariant manner, and so passing them through optical elements (e.g., lenses) would not only change the size but also the profile of the beam. In

Double concave lensuses

While many lasers will output a Gaussian mode, this is not always the most desirable beam profile for a particular application. As we have seen, Gaussian beams have an M2 = 1 and consequently have a low divergence for a given waist size; this makes them suitable for applications where the laser beam must travel a long distance and still maintain some degree of energy concentration. Gaussian beams are also easy to understand in terms of their propagation since they remain invariant in shape, only changing in size following simple analytical rules (see Chapter 1). However, in many applications a flat-top beam profile, sometimes called a top-hat beam, would be more advantageous, for example, in materials processing, lithography, micromachining, and medical applications. In many of these applications, a beamwith a near uniform distribution of energy is desirable: while a Gaussian beam would have a peak energy density of double the average, a flat-top beam would ideally have the same energy density across the entire active area of the beam. In Via drilling this would mean a drill rate that is the same across the area of the hole. In medical applications, say eye surgery, it would mean that the rate of material removal would be equal across the beam and would avoid potential damage due to the large peak energy density at the center of a Gaussian beam. Unfortunately, flat-top beams suffer from some disadvantages: they are not part of the mode set of standard laser resonators and so require custom optics either inside or outside the laser in order to create them; they do not propagate in a shape invariant manner, and so passing them through optical elements (e.g., lenses) would not only change the size but also the profile of the beam. Infact as a general rule, flat-top beams tend not to remain flat-top for very long. However, this can be overcome through a better understanding of the propagation properties of such beams.

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Double concave lensproperties

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For most photographers, focal length is the first thing to consider when choosing a lens as it has a direct relationship with the angle of view, ...

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In use, the optical axis is aligned at 45° to the axis of the incoming polarized light and the thickness of the plate is varied in the plane of the incoming ...

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Jun 30, 2023 — Broadband dielectric mirrors, available in three different spectral ranges from visible, NIR to IR regions, are used to redirect light for ...

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Download scientific diagram | A typical MTF tester design. The whole illumination and test target fixture is mounted on a stage that can move in zdirection ...

Raise the body tube by turning the coarse adjustment knob until the objective lens is about 2 cm above the opening of the stage. Rotate the nosepiece so that ...

fact as a general rule, flat-top beams tend not to remain flat-top for very long. However, this can be overcome through a better understanding of the propagation properties of such beams.

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Light Sources Inc. | 1493 followers on LinkedIn. When Christian L. Sauska and his former business partners established LightSources, Inc. in 1983, ...