Fabrication of low-loss, single-mode-channel waveguide with DNA-CTMA biopolymer by multistep processing technology

All-optical switching in dye-doped DNA nanofibers

All-optical switches are introduced which are based on deoxyribonucleic acid (DNA) in the form of electrospun fibers, where DNA is semi-intercalated with a push-pull, luminescent nonlinear pyrazoline derivative. Optical birefringence is found in the organic nanofibers, with fully reversible switching controlled through continuous-wave laser irradiation. The photoinduced signal is remarkably large, with birefringence highlighted by optically-driven refractive index anisotropy approaching 0.001. Sub-millisecond characteristic switching times are found. Integrating dye-intercalated DNA complex systems in organic nanofibers, as a convenient and efficient approach to template molecular organization and control it by external stimuli, might open new routes for realizing optical logic gates, reconfigurable photonic networks and sensors through physically-transient biopolymer components.

Enhanced nonlinear optical characteristics of copper-ion-doped double crossover DNAs

The modification of deoxyribonucleic acid (DNA) samples by sequencing the order of bases and doping copper ions opens the possibility for the design of novel nanomaterials exhibiting large optical nonlinearity. We investigated the nonlinear characteristics of copper-ion doped double crossover DNA samples for the first time to the best of our knowledge by using Z-scan and four-wave mixing methods. To accelerate the nonlinear characteristics, we prepared two types of unique DNA nanostructures composed of 148 base pairs doped with copper ions with a facile annealing method. The outstanding third-order nonlinear optical susceptibility of the copper-ion-doped DNA solution, 1.19 × 10(-12) esu, was estimated by the conventional Z-scan measurement, whereas the four-wave mixing experiment was also investigated. In the visible spectral range, the copper-ion-doped DNA solution samples provided competent four-wave mixing signals with a remarkable conversion efficiency of -4.15 dB for the converted signal at 627 nm. The interactions between DNA and copper ions contribute to the enhancement of nonlinearity due to structural and functional changes. The present study signifies that the copper-ion-doped double crossover DNA is a potential candidate as a highly efficient novel material for further nonlinear optical applications.

Physically transient photonics: random versus distributed feedback lasing based on nanoimprinted DNA

Room-temperature nanoimprinted, DNA-based distributed feedback (DFB) laser operation at 605 nm is reported. The laser is made of a pure DNA host matrix doped with gain dyes. At high excitation densities, the emission of the untextured dye-doped DNA films is characterized by a broad emission peak with an overall line width of 12 nm and superimposed narrow peaks, characteristic of random lasing. Moreover, direct patterning of the DNA films is demonstrated with a resolution down to 100 nm, enabling the realization of both surface-emitting and edge-emitting DFB lasers with a typical line width of <0.3 nm. The resulting emission is polarized, with a ratio between the TE- and TM-polarized intensities exceeding 30. In addition, the nanopatterned devices dissolve in water within less than 2 min. These results demonstrate the possibility of realizing various physically transient nanophotonics and laser architectures, including random lasing and nanoimprinted devices, based on natural biopolymers.

DNA optical nanofibers: preparation and characterization

We demonstrate the preparation and characterization of DNA optical nanofibers. The prepared DNA optical nanofibers with strong strength and high flexibility are tested. Coupled with silica fiber tapers, their optical characteristics including light transmission performance, group delay and chromatic dispersion are experimentally investigated. The visible and near infrared light waveguiding properties of the DNA optical nanofibers with and without R6G doping are also studied. It is expected that the DNA optical nanofibers may be potential for building the miniaturized biomedical photonic devices.