Divergence of far-infrared laser beam and collimation for Galilean and Keplerian system designs

Optical fiber cleaved at an angle by CO2 laser ablation: Application to micromachining

“…Some specifics about how the beam is controlled will be given later in the next section. In our Keplerian system the input beam diameter D is about 20 mm and was verified by a method reported earlier [13]. For this Keplerian system f 1 = 63.5 mm, f 2 =127 mm and f 3 = 127 mm.…”

“…The separation distance between lenses L 1 and L 2 is 194 mm for an optimal collimation. The optimal collimation was also tested from a method reported earlier [13]. Using Eq.…”

“…Assuming previous data and that the ablation temperature of fused silica [13] to be 2250 1C, using Eq. (2), we find that the energy required to ablate a 125 mm diameter optical fiber is roughly 8.1 mJ.…”

Close up of monochromatic aberrations using Snell's law: an undergraduate computational experiment

“…As a rule of thumb, a spherical refractive surface should face incident parallel rays in order to reduce geometric aberrations [11,12]. In some designs, geometrical aberrations are reduced by positioning the flat refractive surface of a plano-convex lens in such a way that it faces the diverging incident beam [11,12].…”

Application of the ABCD ray matrix method for the design of a refractive 2.5× beam expander–focuser used for coupling laser beams into a 5×4 fiber-optic array: Comparison with Zemax Gaussian and geometrical optics calculations

“…Often Galilean telescopes are used for expanding laser beams in order to increase the size of the beam incident on a focusing lens thereby allowing the beam to be focused to a very small spot [1][2][3][4] at a distance from the laser. Such optical systems are used in laser applications associated with welding, marking, cutting, material processing and surgery.…”