Lasers have been widely used in surface modi® cation. In the present research, a CO 2 continuous wave laser has been used to polish slot surfaces of silica rods. Strong absorption of 10 . 6 l m CO 2 radiation by the silica surface promotes softening of a very thin layer of material that¯ows under the action of surface tension forces. A smooth surface forms, which decreases the surface roughness without substantial change in surface geometry. The effect of laser ± surface inclination angle on the requisite power requirement has been assessed experimentally and theoretically. Using a computer controlled laser beam scanning system, reliability and reproducibility have been greatly improved compared with an alternative surface ® nishing method, manual ® re polishing.MST/5495

The effect of high magnetic field on the microstructure and magnetic properties of α′-FeN films has been studied. The application of a high magnetic field during sputter deposition has a significant influence on the microstructure of α′-FeN films. In particular, the grain growth and the surface roughness are suppressed, and concurrently the coercivity becomes much lower. α′-FeN films deposited in magnetic fields of 2 and 4 T exhibit smooth surfaces with root-mean-square (rms) roughness of, respectively, 0.38–1.53 nm, saturation magnetization of 2.25–2.32 T and coercivity of 1.6–2.6 kA/m, while α′-FeN films deposited at H=0 T show rough surfaces with rms roughness of 6.0–6.8 nm, saturation magnetization of 2.13–2.15 T and coercivity of 9.8–12 kA/m. This effect of high magnetic field on the surface morphology is expected to be widely used to improve various properties of thin films.