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In this report, near-field enhancement around nanoridges and nanotips upon 532nm pulsed laser irradiation is utilized to produce line or dot pattern on gold thin films deposited on glass substrates. The ridges and tips, which have end radii on the order of 50nm, were fabricated out of silicon dioxide thin film on silicon by microfabrication techniques. A 30nm chromium thin film was evaporated onto the ridges or tips by e-beam evaporation to enhance the near-field effect. Line and dot array were successfully patterned on the Au film with feature size ranging from 100 to 200nm. Results from numerical simulation using finite difference time domain method agree with experimental results.

We report on a laser-assisted photothermal imprinting method for directly patterning carbon nanofiber-reinforced polyethylene nanocomposite. A single laser pulse from a solid state Nd:YAG laser (10 ns pulse, 532 nm and 355 nm wavelengths) is used to melt/soften a thin skin layer of the polymer nanocomposite. Meanwhile, a fused quartz mold with micro-sized surface relief structures is pressed against the surface of the composite. Successful pattern transfer is realized upon releasing the quartz mold. Although polyethylene is transparent to the laser beam, the carbon nanofibers in the high density polyethylene (HDPE) matrix absorb the laser energy and convert it into heat. Numerical heat conduction simulation shows the HDPE matrix is partially melted or softened, allowing for easier imprinting of the relief pattern of the quartz mold.

By exciting standing surface acoustic waves (SAWs), a monomer solution can be shaped into a wavy structure. By applying ultraviolet (UV) polymerization, a linear undulate microarray can be fabricated on the polymer material using one-dimensional standing SAWs. When two-dimensional standing SAWs are applied, a latticed microarray, which presents periodically distributed bumps and wells, can be fabricated. The periodicity of the undulate microarray is dependent on the SAW wavelength. Also, the undulating amplitude of the microarray is tunable when applying different input voltages to generate SAWs. The integrated standing SAWs and UV polymerization process provide a rapid method for creating periodic surface patterns.

We report a method to produce nanopatterns on borosilicate glass by a Nd:yttrium–aluminum–garnet laser (10 ns, 1064 nm), using silica nanospheres. Nonlinear absorption of the enhanced optical field between the spheres and glass sample is believed to be the primary reason for the creation of nanofeatures on the glass substrate. By shining the laser beam from the backside of the glass sample, the scattering effects are minimized and only the direct field enhancement due to the spheres is utilized for surface patterning. To confirm this, calculations based on the Mie scattering theory were performed, and the resulting intensity as a function of scattering angles are presented. The nanofeatures thus obtained by this method are 350 nm in diameter and the distance between them is around 640 nm, which is same as the size of spheres used.

We report a Marangoni effect in nanosphere-enhanced laser direct nanopatterning of silicon surface. A monolayer of nanosphere array was formed on the silicon substrate by self-assembly. A 248-nm excimer laser was used to irradiate the sample surface. Due to optical field enhancement between the nanosphere and the substrate, the silicon surface was locally melted. The molten material was redistributed due to surface tension forces, resulting in the formation of a nanodent array. The morphology of the nanodents changed from bowl-type to “Sombrero” with increase of laser intensity as a result of a Marangoni effect that arises due to the competition between a thermocapillary force and a chemicapillary force acting on the molten material.

A photothermal displacement method has been developed to probe the pulsed laser-induced transient melting and surface deformation of Ni–P hard disk substrates. A probing He–Ne laser beam is aligned collinearly with the near-infrared nanosecond pulsed heating beam. The He–Ne beam spot is scanned on the microfeatures formed on the sample surface by the pulsed laser heating. The deflection signals show the variation of the feature shape resulting from different pulse energies of the heating laser beam. The transient deflection signal also reveals that the time scale of the surface motion is in the range of several hundred nanoseconds.

The thermal emission from a Ni–P disk substrate heated by a pulsed excimer laser is measured with nanosecond time resolution. A fast InGaAs photodetector is employed to capture the thermal emission signal. The spectral surface reflectivity is simultaneously measured in situ. The transient surface temperature is derived from the spectral thermal emission signal on the basis of Planck’s blackbody radiation intensity distribution. The experimental results and analytical solutions are compared and an important parameter involving the thermal diffusivity and conductivity in the transient temperature response of the material is evaluated.

We report on the design, fabrication, and analysis of a light-driven micromotor. The micromotor was created from a nanoporous polymer with close-packed gold nanoparticles which generate heat by absorbing light. The blades of the micromotor were curved, forming convex and concave sides. Upon lateral irradiation, by geometric effect the convex side transfers more photon-generated heat to the surrounding gas molecules, causing a convective motion of gas and leading to the rotation of the micromotor. The light-driven motions of gas molecules were analyzed using molecular dynamics modeling.

Microlens array is a key element in the field of information processing, optoelectronics, and integrated optics. Many existing fabrication processes remain expensive and complicated even though relatively low-cost replication processes have been developed. Here, we demonstrate the fabrication of microlens arrays through projection photopolymerization using a digital micromirror device (DMD) as a dynamic photomask. The DMD projects grayscale images, which are designed in a computer, onto a photocurable resin. The resin is then solidified with its thickness determined by a grayscale ultraviolet light and exposure time. Therefore, various geometries can be formed in a single-step, massively parallel fashion. We present microlens arrays made of acrylate-based polymer precursor. The physical and optical characteristics of the resulting lenses suggest that this fabrication technique is potentially suitable for applications in integrated optics.

We describe two techniques for patterning spin-cast thin films of a solution-processable organic semiconductor, triethylsilylethylnyl anthradithiophene (TES ADT), to eliminate parasitic leakage currents and to lower off currents in thin-film transistors. One technique utilizes UV light in the presence of solvent vapors to simultaneously define the active channel and to crystallize TES ADT. The second technique selectively removes TES ADT from the nonchannel regions of the thin-film transistors through direct contact with a poly(dimethylsiloxane) stamp. Both patterning techniques yield thin-film transistors with high charge-carrier mobility (⩾0.1cm2∕Vs), low off currents (10−10–10−11A), and minimal parasitic leakage.

We demonstrate that photolithography can be extended to a subwavelength resolution for patterning of virtually any substrate by exciting surface plasmons on both a metallic mask and a substrate. Without any additional equipment or added complexity to mask design, one-to-one pattern transfer has been achieved. In this letter, a polarized laser beam of 355 nm wavelength was used as light source to photoinitiate an 80 nm thick photoresist on a silicon substrate coated with titanium of 80 nm thick. Array of line apertures of 100 nm in width were made on gold film or titanium film deposited on a quartz substrate, serving as the mask. Simulation results by finite-difference time-domain method have shown that surface plasmons excited on both the metallic mask and the Ti shield help to spatially confine the light behind the apertures. Experimental results show a strong dependence of pattern transfer on the polarization of light as well as the energy dosage of the light. The feature size using such method could be...