We present a numerical comparison of the so-called ‘linear sampling’ inverse scattering methods developed by Colton and Kirsch, published in this journal, and linearized tomographic inverse scattering algorithms based on either holographic filtered backpropagation principles or a plain matrix inversion scheme. Although we restrict ourselves to two-dimensional obstacle scattering, we investigate...

We propose and demonstrate a tunable and switchable dual-wavelength ultra-fast Tm-doped fiber laser. The tunability is based on nonlinear polarization evolution (NPE) technique in a passively mode-locked laser cavity. The NPE effect induces wavelength-dependent loss in the cavity to effectively alleviate mode competition and enables the multiwavelength mode locking. The laser exhibits tunable d...

The design and characterization of a photonic crystal (PC) polarization beam splitter (PBS) that operates with an extinction ratio of greater than 15 dB for both polarizations are presented. The PBS is fabricated on a silicon-on-insulator (SOI) wafer where the input and output ports consist of 5 mum wide ridge waveguides. A large spectral shift is observed in the dispersion plots of the lowest-...

We report low-loss silicon waveguides and efficient grating coupler to couple light into them. By using anisotropic wet etching technique, we reduced the side wall roughness down to 1.2 nm. The waveguides were patterned along the [112] direction on a [110] silicon-on-insulator substrate. The waveguide boundaries are decided by the [111] planes, which are normal to the [110] surface. Fabricated ...

In this work, it is shown that the differential loss between the TE- and TM-polarized fundamental modes in a highly birefringent photonic crystal fiber (PCF) can be enhanced by bending the fiber. As a result, a design approach for single-mode single-polarization operation has been developed and is discussed. A rigorous full-vectorial H-field-based finite element approach, which includes the con...

A nonlinear coefficient of 3.6-4.1  W-1  km-1 and group velocity dispersion of -20  ps2/km of a commercial core-pumped thulium-doped fiber have been evaluated using degenerate four-wave mixing at 2 μm. The anomalous dispersion behavior of the fiber has been confirmed by linear measurements with an all-fiber Mach-Zehnder interferometer (MZI). Additionally, no pum...

Abstract Two-dimensional (2D) materials exhibit fascinating and outstanding optoelectronic properties, laying the foundation for development of novel devices. However, ultra-weak light absorption 2D limits performance Here, a structure MoS 2 /graphene/Au integrated onto side-polished fiber (SPF) is proposed to achieve high-performance fiber-integrated multifunction-in-one device. It found that ...

Transition metal (TM) defects in silicon carbide (SiC) are a promising platform for applications quantum technology. Some TM defects, e.g. vanadium, emit one of the telecom bands, but large ground state hyperfine manifold poses problem which require pure states. We develop driven, dissipative protocol to polarize nuclear spin, based on rigorous theoretical model defect. further show that nuclea...

Bessel beams (BBs) can be generated at microwave frequencies by means of compact, planar devices based on Fabry–Perot cavity leaky-wave resonators. Most designs are the excitation a single transverse magnetic/transverse electric (TM/TE) leaky mode vertical electric/magnetic dipole source. In this work, we analyze important case horizontal magnetic dipole, which excites both TM and TE modes, dev...

Recently, much attention has been paid to second-order photonic topological insulators (SPTIs), because of their support for highly localized corner states with excellent robustness. SPTIs have implemented in either transverse-magnetic (TM) or transverse-electric (TE) polarizations two-dimensional crystals (PCs), and the resultant are polarization dependent, which limits application polarizatio...