Performance of AgGaS₂ Crystal Filter for Raman Spectroscopy

Abstract

We study the level spacing distribution p(s) in the spectrum of random networks. According to our numerical results, the shape of p(s) in the Erdős-Rényi (E-R) random graph is determined by the average degree k and p(s) undergoes a dramatic change when k is varied around the critical point of the percolation transition, k = 1. When k 1, the p(s) is described by the statistics of the Gaussian orthogonal ensemble (GOE), one of the major statistical ensembles in Random Matrix Theory, whereas at k = 1 it follows the Poisson level spacing distribution. Closely above the critical point, p(s) can be described in terms of an intermediate distribution between Poisson and the GOE, the Brodydistribution. Furthermore, below the critical point p(s) can be given with the help of the regularized Gamma-function. Motivated by these results, we analyse the behaviour of p(s) in real networks such as the internet, a word association network and a protein-protein interaction network as well. When the giant component of these networks is destroyed in a node deletion process simulating the networks subjected to intentional attack, their level spacing distribution undergoes a similar transition to that of the E-R graph.

Birefringence of CuGaxAl1 −xSe2crystals

“…The wavelength λ 0 is called the 'isotropic wavelength' (or isotropic point-IP). A large number of crystals that possess an isotropic wavelength have been revealed and studied to date [21][22][23][24][25][26][27][28][29][30][31][32]. The materials with a chalcopyrite structure possess a larger birefringence as compared to crystals with a wurtzite structure.…”

“…The transmission spectra of such crystals, measured with cross-oriented polarizers and the optical axis of the crystal oriented parallel to the polarization of one of the polarizers, are characterized by a narrow transmission band localized at the wavelength of the isotropic point (IP) (i.e. the system works as a band-pass-mode filter) [25][26][27][28][29][30][31][32]. In contrast, a thin absorption line is observed in the same spectral range with parallel-oriented polarizers (band elimination filter).…”

Birefringence of CuGa2S4 crystals

“…The use of single monochromators in combination with narrow band filters with isotropic wavelength is discussed in the literature for this purpose [1][2][3][4][5][6]. Birefringent optically active crystals with isotropic wavelength can be successfully used as optical filters with narrow pass bands.…”

“…The main peculiarity of these filters is the narrow band. The pass band of the filter can be changed by changing the crystal composition, temperature or the external pressure [5][6][7][8].…”

“…A big amount of crystals that possess the isotropic wavelength have been revealed and studied up to date [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. The platelets of AgGaS 2 with λ o wavelength of the optical isotropy ("null wavelength" plates) were used for manufacturing Lyot filters and Solc filters [1,2].…”