Optical polarization

About: Optical polarization is a research topic. Over the lifetime, 13992 publications have been published within this topic receiving 244284 citations.

Surface Plasmon Induced Polarization Splitting Based on Dual-Core Photonic Crystal Fiber with Metal Wire

Abstract: The polarization characteristics of a dual-core photonic crystal fiber (PCF) with a metal wire filled into the cladding air hole between the two cores have been investigated. Numerical investigation shows that the inclusion of the metal wire greatly changes the coupling characteristics of the modes in the two cores. In fact, the coupling lengths of the two polarizations show increased difference, which leads to the possibility of designing a dual-core PCF with a coupling length ratio of 1:2 for the two polarization states. The proposed polarization splitter shows extinction ratios as low as −20 dB with bandwidths as great as 146 nm.

Optical Polarization Characteristics of InGaN Quantum Wells for Green Laser Diodes on Semi-Polar {2021} GaN Substrates

Abstract: The polarization characteristics of InGaN quantum wells on semi-polar {2021} GaN substrates were investigated to reveal the advantageous laser stripe orientation. The polarization ratio exhibited a gradual increase within the range of around 0.2 to 0.3 with an increase in the emission wavelength from 400 to 550 nm under a low current density of 7.4 A/cm2. In addition, the dependence on a current density was quite small up to 0.74 kA/cm2. These results suggest that the laser stripe perpendicular to the a-axis direction is favorable for green laser diodes.

Liquid-crystalline polymers containing heterocycloalkane mesogenic groups. 5. Synthesis of biphasic chiral smectic polysiloxanes containing 2,5-disubstituted-1,3-dioxane- and 2,5-disubstituted-1,3,2-dioxaborinane-based mesogenic groups

Abstract: : The synthesis of side-chain liquid crystalline polysiloxanes containing chiral mesogenic side-groups, is presented. Differential scanning calorimetry and optical polarization microscopy revealed chiral smectic mesomorphism for all polymers. The last two polymers present also a chiral smectic-C mesophase. All copolymers exhibit two glass transition temperatures; one due to the independent motion of the main chain, the other due to the cooperative but independent motion of the side-groups. Therefore, these liquid crystalline copolymers are biphasic systems resembling the behavior of phase separated graft copolymers, i.e., they exhibit a micro-phase separated morphology containing main-chain and side-chain domains.

Tunable Frequency-Quadrupling Dual-Loop Optoelectronic Oscillator

Abstract: A tunable frequency-quadrupling dual-loop optoelectronic oscillator (OEO) based on a polarization modulator is proposed and demonstrated. The introduce of frequency quadrupling in the proposed OEO not only increases the maximal achievable frequency by four times, extends the tuning range by four times, but also enables powerful optical signal processing functions. By incorporating an electrical-tunable yttrium-iron-garnet bandpass filter in the proposed OEO and employing a fiber Bragg grating as a wavelength-fixed optical notch filter, a high-quality microwave signal with a frequency tunable from 32 to 42.7 GHz is generated. The phase noise of the generated frequency-quadrupling signal is also studied.

The Optical Polarization of Near-Infrared Selected QSOs

Abstract: Optical broad-band polarimetry is presented for near-infrared color-selected AGN classified QSOs based on their K-band luminosity. More than 10% of a sample of 70 QSOs discovered in the Two Micron All Sky Survey (2MASS) with J-K > 2 and M_K 3%), and values range to a maximum of P = 11%. High polarization tends to be associated with the most luminous objects at K, and with QSOs having the highest near-IR-to-optical flux ratios. The 2MASS QSO sample includes objects possessing a wide range of optical spectral types. High polarization is seen in two of 22 broad emission-line (Type 1) objects, but 1/4 of the QSOs of intermediate spectral type (Type 1.5-1.9) are highly polarized. None of the nine QSOs classified as Type 2 exhibit P > 3%. It is likely that the unavoidable inclusion of unpolarized starlight from the host galaxy within the observation aperture results in reduced polarization for the narrow emission-line objects. The high polarization of 2MASS-discovered QSOs supports the conclusion inferred from their near-IR and optical colors, that the nuclei of many of these objects are obscured to some degree by dust. The 2MASS QSO sample is compared to other, predominantly radio-quiet, QSOs and is found to be consistent with the idea that the orientation of AGN to the line of sight plays a major role in determining their observed properties.