Long-term changes in Al thin-film extreme ultraviolet filters

Long-term changes in Al thin-film extreme ultraviolet filters

Skinny-film Al filters are very fashionable owing to their excessive transmittance within the wavelength vary of 17-67 nm and low transmittance within the seen and near-UV areas; nonetheless, they’re susceptible to oxidation. The amorphous Al2O3 layers on the Al surfaces have a lot smaller transmittance than the majority Al materials; due to this fact, they strongly affect the overall transmittance of the filter.
This paper not solely supplies the transmittance of very outdated Al filters but additionally maps the transmittance improvement of Al filters over two years since their supply (in 2016) in an uncontrolled environment.

Synchronous measurement of temperature and deformation by an ultraviolet imaging system and monochromatic pyrometry at excessive temperatures

Synchronous measurement of temperature and deformation at elevated temperatures is extremely vital, but difficult in evaluating mechanical properties of thermal safety methods. An ultraviolet (UV) imaging system is proposed to acquire noncontact, in situ, synchronous, and full-field temperature and deformation.
The established system consists of a monochromatic UV illumination with a bandpass filter for radiation suppressing, a UV CCD digital camera for picture capturing, and an infrared pyrometer for temperature recording.
Moreover, an improved monochromatic radiation pyrometry methodology is proposed, whereas a deformation measuring methodology utilizing the UV digital picture correlation (UV-DIC) and pure textures-generated speckle is launched.
Moreover, via digital camera calibration at room temperature and real-time publicity time adjusted at elevated temperatures, the affect of reflection on radiation pyrometry and unfiltered radiation on DIC evaluation is eradicated.
Synchronous temperature and deformation fields of C/SiC subjected to flame heating are experimentally measured with a temperature vary of 500°C-1500°C, and outcomes exhibit the efficacy and potential of the proposed system and methodology. Lastly, the significance of publicity time on balancing the sunshine depth of radiation and reflection can be mentioned.

Era of sub-100 fs ultraviolet pulses from a Kerr-lens mode-locked Ce:LiCAF laser

We report the direct era of mode-locked pulses as brief as 91 fs from the broad-bandwidth achieve medium of LiCaAlF6 (Ce:LiCAF) by combining Kerr-lens mode locking with synchronous pumping.
The latter of those schemes, and the broad bandwidth of Ce:LiCAF, resulted in dispersion tuning of wavelength through cavity size within the spectral area of 290 nm; this mechanism facilitated a sensible technique of estimating intra-cavity dispersion, which was compensated for utilizing a Brewster’s-cut prism pair.
The heartbeat period was measured through split-beam asynchronous cross-correlation utilizing a Ti:sapphire reference laser and a identified time reference. From the Ce:LiCAF laser cavity, output powers of 110 mW and a 9% slope effectivity had been achieved.

Deep- to near-ultraviolet Raman frequency conversion pumped by femtosecond pulses in a hollow-core waveguide

Broadband vibrational/rotational Raman era starting from deep ultraviolet (DUV) to blue wavelengths is demonstrated by utilizing molecular hydrogen in a hollow-core waveguide as a Raman-active medium pumped by a femtosecond DUV laser.
We discover the high-order transient stimulated Raman scattering is drastically enhanced for enter beams together with a circularly polarized part; a circularly polarized enter beam achieves the very best conversion effectivity. Coherent vibrational anti-Stokes Raman emission is noticed just for a circularly polarized pump beam, indicating that the waveguide impact additionally contributes to the upconversion of a DUV pulse through transient stimulated Raman scattering.

Degradation impact of ultraviolet-induced superior oxidation of chlorine, chlorine dioxide, and hydrogen peroxide and its influence on coagulation of extracellular natural matter produced by Microcystis aeruginosa

Implementation of an ultraviolet (UV)-induced superior oxidation course of (AOP) earlier than coagulation was discovered to boost the elimination of algae cells. Nevertheless, the impact of UV-induced AOPs on extracellular mobile natural matter (EOM) and on its coagulation and elimination was uncared for.
This research investigated the influence of UV-induced AOPs (UV/Cl2, UV/ClO2, and UV/H2O2) on EOM from Microcystis aeruginosa, and its coagulation and elimination by a standard gravity system (CGS), dissolved air flotation, and a low-energy flash-pressurized flotation (FPF) course of.
The adjustments in EOM traits earlier than and after the UV-induced AOPs had been primarily based on UV absorbance (UV254) and liquid chromatography with natural carbon detection evaluation. The discount in UV254 elevated with an rising dose of oxidant and UV irradiation. The discount in UV254 for UV/Cl2, UV/ClO2 and UV/H2O2 was 59.5%, 26.5%, and 17.5% respectively, for 0.71 mM equimolar focus of oxidant and 1920 mJ/cm2 UV irradiation, as evident from a pseudo-first order kinetics research.
Equally, degradation of the excessive molecular weight to low molecular weight (LMW) fraction was pronounced for UV/Cl2. The coagulation effectivity decreased after UV-induced AOP within the following order: UV/H2O2 > UV/ClO2 > UV/Cl2. Against this, the low-energy FPF course of confirmed a better elimination of LMW fractions than CGS. Thus, low-energy FPF may very well be an alternate expertise for the UV-induced AOP remedy system.

Diamond step-index nanowaveguide to construction gentle effectively in close to and deep ultraviolet regimes

Two-dimensional metamaterials, consisting of an array of ultrathin constructing blocks, supply a flexible and compact platform for tailoring the properties of the electromagnetic waves. Such flat metasurfaces present a singular answer to bypass the restrictions imposed by their three-dimensional counterparts.
Albeit a number of profitable demonstrations of metasurfaces have been offered within the seen, infrared, and terahertz regimes, and so on., there’s hardly any demonstration for ultraviolet wavelengths as a result of unavailability of the suitable lossless supplies.
Right here, we current diamond as an ultra-low loss materials for the close to and deep ultraviolet (UV) gentle and engineer diamond step-index nanowaveguides (DSINs) to attain full management over the section and amplitude of the incident wave. A complete analytical answer of step-index nanowaveguides (supported by the numerical research) is offered to explain the underlying mechanism of such managed wavefront shaping.
As a result of ultra-low loss nature of diamond in close to and deep UV regimes, our DSINs and metasurfaces designed (from them) exhibit an honest effectivity of ≈ 84% over your entire spectrum of curiosity. To confirm this excessive effectivity and absolute management over wavefront, we’ve designed polarization-insensitive meta-holograms via optimized DSINs for operational wavelength λ = 250 nm.
 Long-term changes in Al thin-film extreme ultraviolet filters

Enhanced efficiency of N-polar AlGaN-based deep-ultraviolet light-emitting diodes

We numerically investigated the efficiency of N-polar AlGaN-based ultraviolet (UV) light-emitting diodes (LEDs) with totally different Al contents in quantum wells (QWs) and boundaries.
We discovered that N-polar buildings may enhance the utmost inside quantum effectivity (IQE) and suppress the effectivity droop, particularly for deep-UV LEDs. In comparison with metal-polar LEDs, N-polar ones retained greater IQE values even when the acceptor concentrations within the p-layers had been one order of magnitude decrease.
The improved efficiency originated from the upper injection efficiencies of N-polar buildings by way of environment friendly service injection into QWs and suppressed electron overflow at excessive present densities.

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