Optical stimulation and silencing of neural activity is a powerful technique for elucidating the structure and function of neural circuitry. In most in vivo optogenetic experiments, light is delivered into the brain through a single optical fiber. However, this approach limits illumination to a fixed volume of the brain. Here a focused ion beam is used to pattern multiple light windows on a tap...

Generation of tunable coherent radiation is numerically investigated via the two-dimensional particle-in-cell (2DPIC) code developed by UNIST [1] and SIMPLEX developed by Spring-8. The electron beams can be produced by the laser-driven wakefield acceleration technique. The electron beam energy can be easily adjusted between 450 MeV and 800 MeV with a tapered density plasma on the order of 1×10 ...

Frequency-chirped free-electron lasers (FELs) are useful to generate a large photon bandwidth or a shorter xray pulse duration. In this paper, we present a threedimensional analysis of a high-gain FEL driven by the energy-chirped electron beam. We show that the FEL eigenmode equation is the same for a frequency-chirped FEL as for an undulator-tapered FEL. We study the transverse effects of such...

This paper presents a technique to expose and characterize nano-structured hole arrays in tapered photonic crystal fibers. Hole array structures are examined with taper outer diameters ranging from 12.9 microm to 1.6 microm. A combined focused ion beam milling and scanning electron microscope system was used to expose and characterize the arrayed air-silica structures. Results from this combine...

In a single gallium nanoparticulate, self-assembled (from an atomic beam) in a nanoaperture at the tip of a tapered optical fiber, we have observed reversible light-induced reflectivity changes associated with a sequence of transformations between a number of structural forms with different optical properties, stimulated by optical excitation at nanowatt power levels. The ability to change the ...