اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدBirefringence of interferential mirrors at normal incidence Experimental and computational study
338
0
0.0
(
0
)
تأليف
Franck Bielsa
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
In this paper we present a review of the existing data on interferential mirror birefringence. We also report new measurements of two sets of mirrors that confirm that mirror phase retardation per reflection decreases when mirror reflectivity increases. We finally developed a computational code to calculate the expected phase retardation per reflection as a function of the total number of layers constituting the mirror. Different cases have been studied and we have compared computational results with the trend of the experimental data. Our study indicates that the origin of the mirror intrinsic birefringence can be ascribed to the reflecting layers close to the substrate.
قيم البحث
اقرأ أيضاً
The refraction of space-time (ST) wave packets offers many fascinating surprises with respect to conventional pulsed beams. In paper (I) of this sequence, we described theoretically the refraction of all families of ST wave packets at normal and obli
que incidence at a planar interface between two non-dispersive, homogeneous, isotropic dielectrics. Here, in paper (II) of this sequence, we present experimental verification of the novel refractive phenomena predicted for `baseband ST wave packets upon normal incidence on a planar interface. Specifically, we observe group-velocity invariance, normal and anomalous refraction, and group-velocity inversion leading to group-delay cancellation. These phenomena are verified in a set of optical materials with refractive indices ranging from 1.38 to 1.76, including MgF$_2$, fused silica, BK7 glass, and sapphire. We also provide a geometrical representation of the physics associated with anomalous refraction in terms of the dynamics of the spectral support domain for ST wave packets on the surface of the light-cone.
In this paper, we build an apparatus for measuring the optical transmittance and its uniformity for a semispherical surface at normal incidence; the system is primarily comprised of a traditional double-beam photometric framework and a novel custom-m
ade mechanical structure with multidimensional degrees of freedom. During the measurement process, a key aligning step is adopted to guarantee that the center point of the semispherical surface stands still in the light beam while scanning the hemispherical optical element point by point around the horizontal and vertical axes, which ensures that the laser beam is always normally incident onto the surface of the hemisphere. The experimental results show that the uniformity of the optical transmittance for a semispherical optical glass can be successfully characterized by the system, with a three-cycle repeatability error of 0.026% being demonstrated. Our system solves the problem of traditional spectrophotometers when measuring the spectral property of a hemispherical surface and thus can be popularized in similar applications.
Two different methods are illustrated to tune multiple reflective bands. For both two types of one-dimensional (1D) photonic crystal (PC) construction, positions of multiple reflective bands can be regulated under certain principles. In addition, the
1D PC heterostructure could be adopted to modulate the relative intensities of reflectance between multiple reflective bands. Structural color is revealed by transforming reflection spectra into CIE coordinates, and the obtained results indicate that CIE coordinate shift occurs due to either band position change or band reflectance variation. The CIE coordinate shift behavior is also influenced by the number of multiple reflective bands. The two approaches reported in this work may provide insights for the application of 1D PC in areas such as displays, sensors, and decoration.
QED vacuum can be polarized and magnetized by an external electromagnetic field, therefore acting as a birefringent medium. This effect has not yet been measured. In this paper, after having recalled the main facts concerning Vacuum Magnetic Birefrin
gence polarimetry detection method and the related noise sources, we detail our Monte Carlo simulation of a pulsed magnetic field data run. Our Monte Carlo results are optimized to match BMV experiment 2014 data. We show that our Monte Carlo approach can reproduce experimental results giving an important insight to the systematic effects limiting experiment sensitivity.
Astronomical X-ray observatories with grazing incidence optics face the problem of pseudo-focusing of low energy protons from the mirrors towards the focal plane. Those protons constitute a variable, unpredictable component of the non X-ray backgroun
d that strongly affects astronomical observations and a correct estimation of their flux at the focal plane is then essential. For this reason, we investigate how they are scattered from the mirror surfaces when impacting with grazing angles. We compare the non-elastic model of reflectivity of particles at grazing incidence proposed by Remizovich et al. (1980) with the few available experimental measurements of proton scattering from X-ray mirrors. We develop a semi-empirical analytical model based on the fit of those experimental data with the Remizovich solution. We conclude that the scattering probability weakly depends on the energy of the impinging protons and that the relative energy losses are necessary to correctly model the data. The model we propose assumes no dependence on the incident energy and can be implemented in particle transport simulation codes to generate, for instance, proton response matrices for specific X-ray missions. Further laboratory measurements at lower energies and on other mirror samples, such as ATHENA Silicon Pore Optics, will improve the resolution of the model and will allow us to build the proper proton response matrices for a wider sample of X-ray observatories.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
