A cw Rhodamine 6G dye laser with a thin optically contacted saturable absorber cell has been mode locked over an operating frequency range of 598–615 nm to produce pulses with durations as short as 0.3 ps. The pulses, with sech2 intensity profiles, are practically bandwidth limited.

The optical absorption and photoluminescence properties of PrTiNbO 6 , NdTiNbO 6 and ErTiNbO 6 crystals grown by laser-heated pedestal growth (LHPG) have been measured at T = 14 K, 77 K and 300 K. These spectra show very high absorption coefficients for the three rare-earth (RE) ions and strong luminescence signals characteristic of ions at high concentration in distorted symmetry sites. The rare-earth ions in these compounds are shown to occupy single sites only. The strong luminescence output at 300 K makes these crystals potential hosts for diode-pumped laser gain media.

In this paper a simple method is described for measuring the principal refractive indices of crystals using a Michelson interferometer and a single principal section of the material. This work formed the basis of the final year BSc project in laser physics and optoelectronics for one of the authors. The refractive indices of a sapphire crystal obtained by this technique are accurate to the third decimal place. The procedure is then used to obtain the three principal refractive indices of a new biaxial crystal, potassium niobium borate, whose refractive indices were previously unknown.

This paper presents the results of a peer review of multimedia materials for teaching and learning electricity and magnetism prepared as a part of the annual activities undertaken by an international group of scientists associated with Multimedia Physics in Teaching and Learning. The work promotes the use of valuable and freely accessible information technology materials for different levels of teaching, mostly higher education. The authors discuss the process of selecting resources and the rubrics used in the rating process. The reviews of high-quality learning resources are presented along with descriptions of valuable didactical features.

Abstract. The generation of the second harmonic of the 632.8 M I light from ao He-Ne laser is described as the basis of an undergraduate experiment. The dependence of the signal on phase-matching angle and intensity of the fundamental beam is discussed.