Hybrid curved nano-structured micro-optical elements.

Tailoring the spatial degree of freedom of light is an essential step towards the realization of advanced optical manipulation tools. A topical challenge consists of device miniaturization for improved performance and enhanced functionality at the micron scale. We demonstrate a novel approach that combines the additive three-dimensional (3D) structuring capability of laser polymerization and the subtractive subwavelength resolution patterning of focused ion beam lithography. As a case in point hybrid (dielectric/metallic) micro-optical elements that deliver a well-defined topological shaping of light are produced. Here we report on hybrid 3D binary spiral zone plates with unit and double topological charge. Their optical performances are compared to corresponding 2D counterparts both numerically and experimentally. Cooperative refractive capabilities without compromising topological beam shaping are shown. Realization of advanced designs where the dielectric architecture itself is endowed with singular properties is also discussed.

Tunable Mid-infrared ZnGeP2 RISTRA OPO pumped by periodically-poled Rb:KTP optical parametric master-oscillator power amplifier.

A laser-diode pumped Q-switched single-frequency Nd:YAG MOPA operating at 100 Hz was used to generate tunable mid-infrared radiation between 6.27 µm and 8.12 µm by employing a cascaded parametric arrangement consisting of degenerate parametric master-oscillator power amplifier using a large aperture periodically-poled Rb:KTiOPO4 which in turn pumped a ZnGeP2 (ZGP) nonplanar RISTRA OPO. The noncollinear ZGP RISTRA tuning behavior is elucidated. The device is aimed for minimally invasive surgery applications at 6.45 µm where the peak power of 193 kW in 5 ns pulses is demonstrated.

Prospects of photosensitization in control of pathogenic and harmful micro-organisms.

Photosensitization is a treatment involving the interaction of the two nontoxic factors, photoactive compound and visible light, which in the presence of oxygen results in the selective destruction of the target cell. Different micro-organisms, such as multidrug-resistant bacteria, yeasts, microfungi and viruses, are susceptible to this treatment. Therefore, a photosensitization phenomenon might open a new avenue for the development of nonthermal, effective and ecologically friendly antimicrobial technology, which might be applied for food safety.

End-box scoring artefact evaluation of the Farnsworth-Munsell 100-Hue colour vision test.

The scoring artefact in the Farnsworth-Munsell 100-Hue test, arising from the grouping of the caps into four boxes, was investigated. The traditional method of scoring performed with the numbers of the anchor caps disregarded and the alternative scoring performed with the numbers of the anchor caps employed, were compared. For the traditional method of scoring, we revealed an increase of the error score of the outside (end-box) caps when the total error score was above 240. On the contrary for scoring performed with the numbers of the anchor caps employed, the difference between the error score of the outside caps and the average error per cap is not significant. To mitigate the end-box artefact and to improve the reliability of the Farnsworth-Munsell 100-Hue test, corrections to the traditional method of scoring are proposed.