Here the exploitation of the laser induced plasma spectroscopy (LIPS) depth profiling in authentication studies of copper alloy and earthenware artifacts was investigated. Such an approach to the discrimination between original and counterfeit objects is based on the examination of the amplitude and shape of elemental distributions along ablation depths of several hundred microns. Thus, its application pass through preliminary assessments and correction of possible systematic errors of the measured profiles, which was the main aim of the present work. LIPS and ESEM-EDX measurements were carried out on two archaeological findings. We show that deep analytical probing produces not negligible intrinsic broadenings of the measured elemental Sn and Ca peaks and propose a correction based on the convolution integral. According to the latter, we demonstrate the actual depth profile can be calculated from the measured one through the experimental determination of the step response and the application of trial-and-error method.
In the present work a non-invasive technological study on three molds from Magnani’s mills in Pescia (Pistoia, Italy)
was carried out. The three molds investigated have been those for making: 1) the invitation letters to the marriage
between Napoleon and Maria Luisa of Austria in 1810; 2) the paper sheets used by Pablo Picasso in 1917 for the
drawings of the Russian Ballets currently preserved in the Picasso Museum in Paris; 3) the holy manuscript Bhagavata
Purana realized in India in 1840 and currently preserved in the “Museum of Art” of San Diego. The chemical
composition of the metal alloy components were investigated and compared using Laser Induced Plasma Spectroscopy
(LIPS), electron microscopy (ESEM-EDX) and Ion Beam Analysis (IBA) while shape and size comparisons were carried
out by means of a homemade 3D digital microscopy device. Metallographic characterizations were also carried out on
some very small samples. This allowed pointing out the different crafting features of the three molds. The results
achieved and represent the first step towards an overall characterization, which will be carried out on Magnani’s mold
For the baseline design of future gravitational wave detection interferometers, use of optical cavities with <i>nonspherical</i>mirrors supporting flat-top ("mesa") beams, potentially capable of mitigating the thermal noise of
the mirrors, has recently drawn a considerable attention. To reduce the severe tilt-instability problems affecting
the originally conceived <i>nearly-flat</i>, "Mexican-hat-shaped" mirror configuration, K. S. Thorne proposed a
<i>nearly-concentric </i>mirror configuration capable of producing the same mesa beam profile on the mirror surfaces.
Subsequently, Bondarescu and Thorne introduced a generalized construction that leads to a one-parameter family
of "hyperboloidal" beams which allows continuous spanning from the nearly-flat to the nearly-concentric
mesa beam configurations. This paper is concerned with a study of the analytic structure of the above family
of hyperboloidal beams. Capitalizing on certain results from the applied optics literature on flat-top beams,
a physically-insightful and computationally-effective representation is derived in terms of rapidly-converging
Gauss-Laguerre expansions. Moreover, the functional relation between two <i>generic</i> hyperboloidal beams is investigated.
This leads to a generalization (involving <i>fractional</i> Fourier transform operators of <i>complex</i> order)
of some recently discovered <i>duality</i> relations between the nearly-flat and nearly-concentric mesa configurations.
Possible implications and perspectives for the advanced Laser Interferometer Gravitational-wave Observatory
(LIGO) optical cavity design are discussed.
The limit sensitivity of interferometric gravitational wave antennas is set by the thermal noise in the dielectric mirror
coatings. These are currently made of alternating quarter-wavelength high/low index material layers with low
mechanical losses. The quarter-wavelength design yields the maximum reflectivity for a fixed number of layers, but not
the lowest noise for a prescribed reflectivity. This motivated our recent investigation of optimal thickness
configurations, which guarantee the lowest thermal noise for a targeted reflectivity. This communication provides a
compact overview of our results, involving nonperiodic genetically-engineered and truncated periodically-layered
configurations. Possible implications for the advanced Laser Interferometer Gravitational wave Observatory (LIGO) are
Mirror thermal noise is one of the fundamental factors limiting the sensitivity of gravitational wave interferometric detectors. Classical Gaussian beams "interrogate" only a small fraction of the mirror surface, and therefore are not well suited to average out fluctuations and minimize the thermal noise. It has been calculated that flat beam profiles would be better suited to average over thermal fluctuations and would allow sensitivity improvements that would more than double the "reach" of GW interferometric detectors. Non-spherical mirrors, shaped to support flat beam profile beams, have been designed and fabricated. A dedicated interferometer has
been built to test the performance of these mirrors. We report on the
status of this development.