Focus movement distance per pulse dependence of electrical conductivity and diameter of diamond internal modification induced by picosecond laser.

Internal and local modifications via ultrashort pulsed laser illumination to diamond are promising for manufacturing diamond electronic devices. The relationship between the diameter/electrical conductivity of modified regions and the laser fluence distribution was investigated. Picosecond laser illumination without scanning the laser focus fabricated short modified regions in diamond.

Local control of optical absorption properties of glass using precipitation of gold nanoparticles via gold sphere movement driven by laser.

Glass embedded with metal nanoparticles is a promising material necessary for optical devices because of its absorption properties associated with the surface plasmon resonance (SPR) of metal nanoparticles. We demonstrated that continuous-wave laser illumination of the metal sphere in glass migrates the metal sphere and dopes the migration trajectory. In this study, we have attempted to locally control the absorption properties of borosilicate glass via gold nanoparticle precipitation using gold sphere migration.

Clarification of fast metal sphere movement in glass.

In this study, metal spheres were implanted into glass by continuous-wave (CW) laser illumination, which manipulated the metal sphere inside the glass. The spheres moved at approximately 100 mm/s, which is 100 times faster compared to conventional movement. The movement mechanism was clarified by in situ, cross-sectional, and microscopic observations.

Compositional redistribution in CaO-AlO-SiO glass induced by the migration of a steel microsphere due to continuous-wave-laser irradiation.

A high-power continuous-wave (CW) laser was used to move a steel microsphere through a CaO-AlO-SiO glass block at room temperature along a trajectory toward the laser source. A compositional analysis revealed that the CaO concentration in the glass decreased at the center of the microsphere's trajectory but increased in the area adjacent to it; the SiO concentration showed an opposite trend while the AlO concentration did not change. Further, the compositional difference between the center and the area adjacent to the microsphere trajectory depends on the velocity of the microsphere, which is controllable by tuning the laser power.

Experimental and theoretical study on the driving force and glass flow by laser-induced metal sphere migration in glass.

Light is able to remotely move matter. Among various driving forces, laser-induced metal sphere migration in glass has been reported. The temperature on the laser-illuminated side of the sphere was higher than that on the non-illuminated side.

Picosecond optical vortex pulse illumination forms a monocrystalline silicon needle.

The formation of a monocrystalline silicon needle by picosecond optical vortex pulse illumination was demonstrated for the first time in this study. The dynamics of this silicon needle formation was further revealed by employing an ultrahigh-speed camera. The melted silicon was collected through picosecond pulse deposition to the dark core of the optical vortex, forming the silicon needle on a submicrosecond time scale.

Moving force of metal particle migration induced by laser irradiation in borosilicate glass.

We optically manipulated a metal particle in borosilicate glass. The glass in the neighborhood of the laser-heated metal particle softened; hence, the metal particle was able to migrate in the glass. In this letter, the driving force of the metal particle toward the light source in the glass provided by laser illumination was investigated.

Metal particle manipulation by laser irradiation in borosilicate glass.

We propose a new technique of manipulating a metal particle in borosilicate glass. A metal particle that is heated by laser illumination heats the surrounding glass by radiation and conduction. A softened glass enabled metal particle migration.

The effect of micronscale anisotropic cross patterns on fibroblast migration.

Cell movement on adhesive surfaces is a complicated process based on myriad cell-surface interactions. Although both micron and nanoscale surface topography have been known to be important in understanding cell-materials interactions, typically only simple patterns (e.g.

Fabrication of arbitrary polymer patterns for cell study by two-photon polymerization process.

Topographically patterned surfaces are known to be powerful tools for influencing cellular functions. Here we demonstrate a method for fabricating high aspect ratio ( approximately 10) patterns of varying height by using two-photon polymerization process to study contact guidance of cells. Ridge patterns of various heights and widths were fabricated through single laser scanning steps by low numerical aperture optics, hence at much higher processing throughput.

Self-standing aligned fiber scaffold fabrication by two photon photopolymerization.

Development of materials and fabrication techniques lead the growth of three-dimensional cell culture matrices in biomedical engineering. In this work, we present a method for fabricating self-standing fiber scaffolds by two-photon polymerization induced by a femtosecond laser. The aligned fibers are 330 microm long with a diameter of 6-9 microm.