Optical vortex switch based on multiplexed volume gratings with high diffraction efficiency.

Systems of controllable orbital angular momentum (OAM) require more compact, higher conversion efficiency and more tolerable wavelength or polarization. We introduce an optical vortex switch based on a multiplexed volume grating (MVG). The MVG recorded in a piece of photo-thermo-refractive (PTR) glass exhibits high diffraction efficiency (DE, also known as conversion efficiency in transporting), sensitive angular selectivity, and polarization-insensitivity.

Fabrication of high-precision reflective volume Bragg gratings.

Reflecting Bragg gratings (RBGs) recorded in photo-thermo-refractive (PTR) glasses have been widely used in narrowing and stabilization of the laser emission spectrum. As the center wavelength of RBGs determines the final output wavelength of lasers, it is necessary to carefully control the center wavelength of RBGs during the fabrication process. In this paper, the fabrication process of high-precision RBGs was investigated.

Design and fabrication of multiplexed volume Bragg gratings as angle amplifiers in high power beam scanning system.

In this study, the realization of multiplexed volume Bragg gratings (VBGs) working as angle amplifiers in high power beam scanning system is theoretically and experimentally investigated. The design of the multiplexed VBG for the working wavelength of 1064 nm is described. We propose a cascaded multiplexed VBGs scheme that consists of 12 grating channels.

Method for precise evaluation of refractive index modulation amplitude inside the volume Bragg grating recorded in photo-thermo-refractive glass.

In this paper, we present a method for achieving precise evaluation of amplitude of refractive index modulation (RIM) inside the volume Bragg grating (VBG) recorded in photo-thermo-refractive (PTR) glasses. The Gaussian divergence characteristics of the incident beam is theoretically considered when calculating the angular selectivity of VBG, and the profiles of experimental angular selectivity curves are utilized to determine the value of RIM with one step. The effectiveness of our proposed method is experimentally verified.

Manipulation of dual band ultrahigh index metamaterials in the terahertz region.

By drastically decreasing the diamagnetic effect with a thin metallic structure in the unit cell and increasing the effective permittivity through strong capacitive coupling, we designed the crossed I-shaped metallic patches metamaterial with an extremely high refractive index in the dual band terahertz region. The peak index of refraction of near 80 at about 0.75 THz is predicted, along with another peak index of about 25 at 2.

Detection of low-level DNA mutation by ARMS-blocker-Tm PCR.

Background: Low-level DNA mutations play important roles in cancer prognosis and treatment. However, most existing methods for the detection of low-level DNA mutations are insufficient for clinical applications because of the high background of wild-type DNA.

Design And Method: In this study, a novel assay based on Tm-dependent inhibition of wild type template amplification was developed.