Carbon Nanotube Porins in Amphiphilic Block Copolymers as Fully Synthetic Mimics of Biological Membranes.

Biological membranes provide a fascinating example of a separation system that is multifunctional, tunable, precise, and efficient. Biomimetic membranes, which mimic the architecture of cellular membranes, have the potential to deliver significant improvements in specificity and permeability. Here, a fully synthetic biomimetic membrane is reported that incorporates ultra-efficient 1.5 nm diameter carbon nanotube porin (CNTPs) channels in a block-copolymer matrix. It is demonstrated that CNTPs maintain high proton and water permeability in these membranes. CNTPs can also mimic the behavior of biological gap junctions by forming bridges between vesicular compartments that allow transport of small molecules.

Microstructure fiber optical parametric oscillator with femtosecond output in the 1200 to 1350 nm wavelength range.

We describe an ultrafast fiber optical parametric oscillator operating in the 1210 nm to 1340 nm wavelength range. The system consists of a microstructure fiber placed in a Fabry-Perot cavity which is optically pumped with 1030-nm light from an Ytterbium mode-locked fiber laser. The output wavelength is tunable over a 130-nm span by adjusting the position of one cavity mirror. SHG FROG measurements reveal that the output pulse quality varies as a function of pump power and wavelength. Ultrafast sources operating in this range are particularly instrumental for deep-tissue nonlinear biophotonics applications.

Generation of sub-100-fs pulses from a microstructure-fiber-based optical parametric oscillator.

We report on the generation of 70-fs pulses at a center wavelength of 880 nm using a microstructure-fiber-based optical parametric oscillator pumped by a fiber laser operating at 1032 nm. We present optical spectra and autocorrelation measurements that illustrate the generation of ultrashort pulses and the onset of saturation at sufficiently high pump powers. Generation of ultrafast pulses with nanojoule energies provides new opportunities for extending the functionality of mode-locked fiber lasers.