There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

Selective laser melting of aluminium components

Single track formation in selective laser melting of metal powders

Surface roughness analysis, modelling and prediction in selective laser melting

The three-dimensional (3D) theory of laser cutting is presented. The cutting efficiency determined by its ultimate parameters at different types of polarization is estimated. The physical reasons for limitations of ultimate cutting parameters at a plane P-polarized beam are displayed. In the case of cutting metals with a large ratio of sheet thickness to width of the cut, the laser cutting efficiency for a radially polarized beam is 1.5 - 2 times larger than for plane P-polarized and circularly polarized beams. The possibility of generating the radially polarized beam is discussed.

https://iopscience.iop.org/article/10.1088/0022-3727/32/13/304/pdf

Influence of beam polarization on laser cutting efficiency

In the laser treatment of a workpiece (9), e.g. for surface hardening, melting, alloying, cladding, welding or cutting, the adverse effect of reflectivity of the surface, when a pure, monochromatic laser (6) is used, is remedied by the simultaneous application of a relatively shorter wavelength beam (1). The two beams (1)(5) may be combined by a beam coupler (4) or may reach the workpiece (9) by separate optical paths (not shown). The shorter wavelength beam (1) improves the coupling efficiency of the higher- powered laser beam (5).

William Maxwell Steen

Papers

Laser Material Processing