Arbitrary Engineering of Spatial Caustics with 3D-printed Metasurfaces

Caustics occur in diverse physical systems, spanning the nano-scale in electron microscopy to astronomical-scale in gravitational lensing. As envelopes of rays, optical caustics result in sharp edges or extended networks. Caustics in structured light, characterized by complex-amplitude distributions, have innovated numerous applications including particle manipulation, high-resolution imaging techniques, and optical communication. However, these applications have encountered limitations due to a major challenge in engineering caustic fields with customizable propagation trajectories and in-plane intensity profiles. Here, we introduce the compensation phase via 3D-printed metasurfaces to shape caustic fields with curved trajectories in free space. The in-plane caustic patterns can be preserved or morphed from one structure to another during propagation. Large-scale fabrication of these metasurfaces is enabled by the fast-prototyping and cost-effective two-photon polymerization lithography. Our optical elements with the ultra-thin profile and sub-millimeter extension offer a compact solution to generating caustic structured light for beam shaping, high-resolution microscopy, and light-matter-interaction studies

Spectrally Selective Solar Absorbing Coatings Prepared by dc Magnetron Sputtering

Spectrally selective solar absorber using composite Ni-NiO as coating materials was studied. Samples were prepared by dc magnetron sputtering unit named Rulle, which is a miniature copy of an industrial roll-coater unit. Using asymmetric location of the oxygen nozzele, it is possible to form the desired metallic concentration distribution along the sputtering zone under optimized conditions. This distribution can be transferred into a graded film profile by moving the substrate, obtaining good spectral selectivity. For specified mechanical settings (such as locations of gas sprays, target and pump positions etc.), the ratio of used oxygen flow to the corresponding critical oxygen flow, RO, is a dimensionless parameter to control the zone specification. The optimal value is around 0.80 for the Rulle. Optimized zone shows properties with two main parts: the metallic composite part of varied nickel volume fraction and the dielectric part. Two parts of the sputtering zone can form a graded absorbing layer with the right ratio of base and middle layer by the moving substrate technique. Distribution of normalized conductivity, NC, along the absorbing sputtering zone is a simple and good specification of zone property. Profile of graded film prepared by the moving substrate technique can be tailored according to NC distribution. XRD and XPS study confirms the NC results. Simulation reveals that absorption should mainly rely on the intrinsic, but less on the interference mechanism. Used metallic volume fraction of Ni-NiO is 0.3 for main absorbing layer. The front surface reflection loss due to high refractive index can be reduced by adding a layer with low refractive index on the top. Simulation shows that three-layer coatings are a good and simple coating structure. High solar absorptance of 0.97 has been achieved with low thermal emittance of 0.05 by theoretical simulation as well as experimentally prepared samples

"Trusteeship for an estate"

Mantojuma aizgādnības institūta būtība ir radīt efektīvu mehānismu, kas nodrošinātu pilvērtīgu mantojuma darbību līdz brīdim, kamēr mantinieki tiek apstiprināti mantojuma tiesībās. Tā mērķis ir nodrošināt mantojuma saglabāšanu. Lai gan normatīvajos aktos nesen tika veikti grozījumi, kas paredz mantojuma aizgādnības funkciju veikt zvērinātiem notāriem, nevis tiesai, tādējādi paātrinot šo procesu, regulējums vēl joprojām ir smagnējs un laikietilpīgs. Bakalaura darba mērķis ir izpētīt normatīvajos aktos veiktos grozījumus, konstatēt esošos problēmjautājums un rast iespējamos risinājums, kas nodrošinātu mantojuma aizgādnības institūta realizēšanu atbilstoši tā mērķim. Darba izstrādes gaitā tiek pētīti un analizēti normatīvie akti, tiesu nolēmumi, kā arī tiek veiktas konsultācijas ar nozaru speciālistiem. Bakalaura darba ietvaros autore piedāvā grozīt un papildināt spēkā esošo regulējumu, kas ievērojami atvieglotu mantojuma aizgādnības institūta pielietošanu. Atslēgvārdi: mantojuma aizgādnība, mantojuma aizgādnis, mantojuma pārstāvība, mantojuma apsardzība, mantojums, mantojuma masa, zvērināts notārs, bāriņtiesa.Trusteeship of an estate institute point of matter is to create an effective mechanism, to ensure full estate activity until heirs are approved under inheritance law. The aim of it is to ensure keeping estate. Although laws and regulations recently have been amended, which provides trusteeship of estate function to manage sworn notaries, not a court, thus speeding the process up. The regulation is still heavy and time consuming. Aim of the bachelor thesis is to explore amendments in law, establish existing issues and find possible solutions, which provides trusteeship of an estate institute implementation according to its purpose. In course of developing paper, are studied and analyzed regulatory enactments, court judgments, as well as are caried out the consultations with experts of this field. In framework of bachelor thesis the author offers to amend and improve existing law in force, which considerably would relieve trusteeship of an estate insitute usability. Keywords: trusteeship of an estate, trustee of an estate, representation of an estate, protection of an estate, estate, entirety of property of an estate, notary public, orphan’s court

Chromaticity and Optical Properties of Colored and Black Solar-Thermal Absorbing Coatings

Two important trends in solar thermal utilization in buildings are building integration and color appearance. Coatings based on titanium alloy nitride show variety of different colors. These can be controlled by film thickness for a single layer stack, or by putting another layer on top of the first layer. Strong absorption around 500 nm is important to cause color appearance. Chromaticity and optical properties of colored coatings were studied and compared to black coatings. In the three-point gamut system, such colors show an additive mixture property. Solar absorptance of 0.80 to 0.95 can be obtained with thermal emittance of 0.04 to 0.09 (100oC). These coatings provide a choice for solar thermal integration in buildings where appearance is an important feature

Information society assessment of development level in Latvia

Maģistra darba tēma ir „Informācijas sabiedrības attīstības līmeņa novērtēšana Latvijā”. Maģistra darba mērķis ir, pamatojoties un teorētisko un praktisko materiālu apkopojumu, aprakstīt un novērtē informācijas un komunikāciju tehnoloģiju nozīmi, lai veiksmīgi novērtētu informācijas sabiedrību, kas sniedz ieskatu par valsts kopējo attīstības līmeni un konkurētspēju. Darba gaitā tika izdarīti secinājumi par Latvijas informācijas sabiedrības attīstību starp Eiropas Savienības valstīm pēc statistiskiem rādītājiem un aprakstošiem indeksiem, kas parāda, ka Latvija attīstības līmenis ir zemāks nekā Eiropas Savienības vidējais līmenis. Darbs ir sadalīts 3 nodaļās un 10 apakšnodaļās. Maģistra darba apjoms ir 64 lappuses, kas ietver 16 tabulas, 22 attēlus, 1 pielikumu un 28 informatīvais avots. Atslēgas vārdi: informācijas un komunikāciju tehnoloģijas, internets, e – pakalpojumi, informācijas sabiedrības indekssThe theme of the master’s thesis is „Information society assessment of development level in Latvia”. The purpose of the master's thesis, based on the theoretical and practical material collection, is to describe and evaluate the information and communication technologies in order to successfully evaluate the information society, which provides an insight into the country's overall development and competitiveness. The course of the work the conclusions were made about Latvian Information Society of the European Union countries by the descriptive statistical indicators and indices, showing that the level of development of Latvia is lower than the European Union average. The paper is divided into 3 chapters and 10 subchapters. The amount of the master’s thesis is 64 pages that include 16 tables, 22 images, 1 appendix and 28 information sources. Keywords: information and communication technologies, the Internet, e - services, Information Society Inde

The influence of oxygen in TiAlOxNy on the optical properties of colored solar-absorbing coatings

Low cost and ease of fabrication are important factors for solar-thermal applications in energy-efficient buildings. This contribution reports the influence of oxygen on structure, optical properties and chromaticity of TiAlOxNy thin films prepared by DC magnetron sputtering. It is an extension of a previous study on colored solar-thermal absorbers based on titanium-aluminum nitride. The purpose is to investigate the possibility of using TiAlOxNy as middle layer to achieve a gradient effect. The results reveal that the structure and optical properties of the TiAlOxNy coatings are sensitive to the oxygen content under certain sputtering conditions.  The ratio of oxygen/nitrogen of 0.7:10 is the most appropriate to form the crystalline structure of TiAlON.  The optical constants of TiAlN and TiAlON were deduced by fitting the experimental data. It shows that both the refractive index (n) and the extinction coefficient (k) are decreased when oxygen is introduced to form titanium-aluminium nitro-oxide. The gradient effect can be achieved and controlled by adjusting the ratio of oxygen/nitrogen flow during the process to enhance solar absorptance while keeping the desired color appearance

Colour control and selectivity in TiAlN solar-thermal absorbers

ABSTRACT Optical constants for simulations were obtained by R-and T-measurements on TiAlN thin films deposited on Corning 7059 glass. The model parameterized free carrier effects and an inter-band excitation. The calculations demonstrated that the colour effects are due to interference and inter-band absorption around 500 nm in a single layer coating. The peak shifts with the thickness of the thin film which gives a simple way to obtain different colours. Solar absorptance of 86 % can be reached already for a single TiAlN-film on an Al substrate