Ground-Based Ultraviolet-Radiation Measurements during Springtime in the Southern Hemisphere

We report the first measurements obtained by a network of UV-B detectors established through Argentina and Chile, at locations covering latitudes extending from 53°S to 18° S. Evidence that UVB increases are detected at these latitudes during the Austral spring 1993 is presented

Ground-based ultraviolet-radiation measurements during springtime in the Southern hemisphere

We report the first measurements obtained by a network of UV-B detectors established through Argentina and Chile, at locations covering latitudes extending from 53°S to 18° S. Evidence that UVB increases are detected at these latitudes during the Austral spring 1993 is presented. The destruction of the stratospheric ozone layer is generally considered one of the most serious environmental problems. It has been recently published that during October 1998 the ozone hole has been the deepest ever recorded. Reduction of the stratospheric ozone layer was un ambiguously detected about two decades ago in the Antarctic continent. Since then it has been systematically monitored by different means (satellite, balloon soundings and ground station observations. One of the most serious content reduction is the increase of biologically effective ultraviolet doses, particularly the so-called ultraviolet B radiation (280-320 nm) received at the Earth surface, with multiple possible hazards for living species. Despite these consequences, ground stations to check the UV Sun radiation are not very numerous, particularly outside the circumpolar area in the Southern Hemisphere. With the aim of studying whether the ozone depletion over the Antarctic area has extended further, and whether the possibility that UV radiation increase may begin to affect inhabited regions, a network of UVB detectors has been established through Argentina and Chile, at locations covering latitudes extending from 53°S to 18° S. Here we report the first measurements obtained by this network providing evidence that UVB increases are detected at these latitudes during the last Austral spring.Facultad de Ciencias Exacta

Ground-based ultraviolet-radiation measurements during springtime in the Southern hemisphere

We report the first measurements obtained by a network of UV-B detectors established through Argentina and Chile, at locations covering latitudes extending from 53°S to 18° S. Evidence that UVB increases are detected at these latitudes during the Austral spring 1993 is presented. The destruction of the stratospheric ozone layer is generally considered one of the most serious environmental problems. It has been recently published that during October 1998 the ozone hole has been the deepest ever recorded. Reduction of the stratospheric ozone layer was un ambiguously detected about two decades ago in the Antarctic continent. Since then it has been systematically monitored by different means (satellite, balloon soundings and ground station observations. One of the most serious content reduction is the increase of biologically effective ultraviolet doses, particularly the so-called ultraviolet B radiation (280-320 nm) received at the Earth surface, with multiple possible hazards for living species. Despite these consequences, ground stations to check the UV Sun radiation are not very numerous, particularly outside the circumpolar area in the Southern Hemisphere. With the aim of studying whether the ozone depletion over the Antarctic area has extended further, and whether the possibility that UV radiation increase may begin to affect inhabited regions, a network of UVB detectors has been established through Argentina and Chile, at locations covering latitudes extending from 53°S to 18° S. Here we report the first measurements obtained by this network providing evidence that UVB increases are detected at these latitudes during the last Austral spring.Facultad de Ciencias Exacta

Estudio del centro laser F+2

Centro de Informacion y Documentacion Cientifica (CINDOC). C/Joaquin Costa, 22. 28002 Madrid. SPAIN / CINDOC - Centro de Informaciòn y Documentaciòn CientìficaSIGLEESSpai

Scanning near-field transmission and confocal micro-spectroscopy characterization of direct laser written rare-earth doped lithium niobate three-dimensional photonic crystals

Reports on the optical micro-characterization of direct laser written rare-earth doped lithium niobate threedimensional photonic crystals. The femtosecond laser microstructural changes inside lithium niobate are first studied by a combination of confocal micro-Raman, rare-earth micro-luminescence and scanning near-field back-scattering microscopy, revealing a complex three-dimensional topology consisting of amorpohus (low index), unmodified (matrix index), and compressed (high index) lithium niobate. Further scanning near-field transmission images reveal specific features such as optical channeling which are not observed in far-field optical microscopy, and are theoretically interpreted in terms of the previous observed three-dimensional topologies

Near-field imaging of femtosecond laser ablated sub-lambda/4 holes in lithium niobate

We report on the direct femtosecond laser ablation of sub-lambda/4 (80–250 nm) holes in LiNbO3 crystals and on its local near-field imaging. We show that the near-field transmission of holes can feature an attenuation of ~75% at hole central position, and a ~20% transmission enhancement at its sides. This high-contrast ring-shaped near-field distribution is found to be in agreement with simulations, suggesting the surface relief as the main contrast mechanism