Hyperbolic metamaterials (HMMs) are artificial extreme anisotropic media, which are characterized by indefinite or hyperbolic dispersion relation where the out-ofplane dielectric constant has an opposite sign to the in-plane dielectric constants. [1] These effective bulk metastructures are usually composed of metallic and dielectric elements, and display extraordinary optical properties over a wide frequency band from visible to terahertz. The HMMs showing hyperbolic dispersion can be classified based on the sign of their dielectric components, such as type I (−ε ⊥ and ε ll ) and type II (ε ⊥ and − ε ll ). The type I HMM is usually realized using metallic nanowires immersed in a dielectric matrix, [2] while the type II HMM assumes stacked metal/dielectric multilayers. [3] In particular, the type II is the most studied HMM because of its straightforward fabrication using conventional thin film physical vapor deposition (PVD) techniques. Various metal-dielectric multilayer stacks have been proposed to realize hyperbolic dispersion over the frequency band from visible to terahertz. [1][2][3][4][5][6][7] In recent years, the type II multilayered HMMs have received much attention and used as the technological core in many potential applications including ultrasensitive biosensors, [8][9][10] absorbers, [11,12] single photon sources, [13] super-resolution imaging, [14] and Cherenkov radiation. [15] In addition, thermal flux engineering has been achieved using HMMs, [16] which is considered to be the near-field analog of a blackbody. Also, the occurrence of super-Planckian thermal energy transfer has been predicted in HMMs. [17] The overall optical response of HMM can be qualitatively predicted in the framework of the so-called effective medium theory (EMT) since both the layers of HMMs are deeply subwavelength. [18] In particular, HMM is a 1D subwavelength photonic crystal when stacking multiple periodic bilayers of metal/dielectric is formed. The optical response of HMM can be homogenized if the number of bilayers in the stack is large enough and their thickness is deeply subwavelength. Therefore, the overall uniaxial optical response can be described using an effective dielectric permittivity, whose components (parallel and perpendicular to the surface of HMM) can be calculated by applying boundary conditions. [19] HMM supports both radiative and nonradiative guided modes. Bulk plasmon polariton (BPP) [20] or high-k optical Hyperbolic metamaterials (HMMs) are used to demonstrate extreme sensitivity biosensing by exciting their high-k modes. However, momentum couplers, such as subwavelength diffraction grating or bulky high-index prism, are required to excite these nonradiative modes, which is not cost-effective and thus not suitable for point-of-care applications. Here, a cost-effective and scalable HMM-based sensor platform is proposed and experimentally demonstrated, by exciting the Brewster mode of HMM from free-space. The excitation of Brewster modes is shown in a multilayered HMM comprising of alternating thin l...

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In this paper, a generalized nonlinear Schrödinger–Maxwell–Bloch model with variable dispersion and nonlinearity management functions, which describes the propagation of optical pulses in an inhomogeneous erbium-doped fiber system under certain restrictive conditions, is under investigation. We derive the Lax pair with a variable spectral parameter and the exact soliton solution is generated from the Bäcklund transformation. It is observed that stable solitons are possible only under a very restrictive condition for the spectral parameter and other inhomogeneous functions. For various forms of the inhomogeneous dispersion, nonlinearity and gain/loss functions, construction of different types of solitary waves like classical solitons, breathers, etc is discussed.