Although optical absorption is an intrinsic materials property, it can be manipulated through structural modification. Coherent perfect absorption increases absorption to 100% interferometrically but is typically realized only over narrow bandwidths using two laser beams with fixed phase relationship. We show that engineering a thin film's photonic environment severs the link between the effect...

HST UV observations of V795 Her reveal a strong 2.6-h orbital variation in the prominent UV lines, in contrast to earlier (IUE) evidence of a 4.8-h period. Only the Civ line contains a strong blue-shifted, wind formed absorption component. Several lines exhibit a 'narrow' absorption feature near rest velocity which may originate in the disk, and a blue-shifted emission feature which accounts fo...

We present a novel photoacoustic detection system with a high pressure C02 laser as radiation source. The laser is continuously tunable across wavelength ranges from 13 cm-I to 18 cm-1 wide. The narrow bandwidth of 0.017 cm-1 allows to resolve any fine structure in the absorption spectra of trace gases at atmospheric pressure. The absorption spectra of four gases are reported, demonstrating the...

Zinc oxide thin films grown by atomic layer deposition have been subject to great attention over the past few years. In this work, we study ZnO on Si substrates with di-ethyl zinc (DEZ) as metal precursor and H2O or D2O water vapour oxidant. Film composition a function of growth temperature is studied Ion Beam Analysis (IBA) using Rutherford Backscattering Spectrometry (RBS) determine Zn areal ...

We employ three highly sensitive spectrometers: a photoacoustic spectrometer, a photothermal common-path interferometer and a whispering-gallery-resonator-based absorption spectrometer, for a comparative study of measuring the absorption coefficient of nominally transparent undoped, congruently grown lithium niobate for ordinarily and extraordinarily polarized light in the wavelength range from...

todays, in many modern applications, we search for frequent and repeating patterns in the analyzed data sets. in this search, we look for patterns that frequently appear in data set and mark them as frequent patterns to enable users to make decisions based on these discoveries. most algorithms presented in the context of data stream mining and frequent pattern detection, work either on uncertai...

High Power microwave vacuum windows are an essential component in developing 1 MW/CW gyrotrons. The thesis focuses on thermal and mechanical analysis of three different microwave window designs. These include the present double disk window, a distributed window being developed by General Atomics and a single-disk diamond window design. The output microwave window is currently the limiting facto...