Thin films of DNA biopolymer thin film are fabricated by a drop casting process on glass and silicon substrates, as well as freestanding. The refractive index is measured by elliposmetry and in bulk DNA film the refractive index is shown to be increased in the 600 to 900 nm DNA transparency window by doping with riboflavin. Further analysis with FT-IR, Raman, and XRD are used to determine whether binding between riboflavin and DNA occurs.
Bessel beams are important for applications in optical trapping because they have non-diffracting and self-reconstructing properties. We fabricated a fiber device to generate a Bessel-like beam that is significantly more compact than a conventional bulk-optic Bessel beam generation system. Micro-scale dielectric particles in water are trapped and transported along the optical route formed by this Bessel-like beam. By controlling the speed and angular motion of the particles, we have demonstrated optically induced circulation of particles along triangular routes. This technique is applicable to the control of motion of living cells in a microscopic environment.
We report development of a new kind of micro-optical waveguide based on liquid core in a V-groove glass and air cladding and a similar finite element method was constructed to investigate the guiding properties such as mode distribution and modal birefringence. Through the detailed modeling, we investigate the role of each parameter such as, refractive index of core and diameter of core of V-groove structure. This work demonstrates numerically and experimentally high birefringence in this optical waveguide and different aspects of the fiber properties related to the fundamental mode and fiber birefringence are revealed. As a result, wave-guide with large birefringence is identified for opening angle of 40 degree and refractive index of 1.472.