Heating of opaque surfaces by picosecond laser pulses

Received: 5 June 1997/Accepted: 13 June 1997     

Laser-induced dry etching of integrated InP microlenses

Received: 4 June 1997/Accepted: 13 June 1997     

Laser ablation from Lithium niobate

Received: 21 May 1997/Accepted: 4 July 1997     

Sulfur-modified surface of InP(001): Evidence for sulfur incorporation and surface oxidation

Received: 21 March 1997/Accepted: 12 August 1997     

PET surface modifications by treatment with monochromatic excimer UV lamps

Received: 11 August 1997/Accepted: 14 August 1997     

Study of visual inspection and control methods of effectiveness of laser shock-processing

Received: 29 October 1996/Accepted: 16 May 1997     

Micromachining of quartz with ultrashort laser pulses

Received: 6 January 1997/Accepted: 1 April 1997     

Dynamics of the hydrodynamical growth of columns on silicon exposed to ArF excimer-laser irradiation

Received: 6 January 1997/Accepted: 8 July 1997     

Modeling of infrared soft-tissue photoablation process

Received: 2 September 1996/Revised version: 17 February 1997     

Generation of submicron surface gratings on LiNbO3 by ultrashort UV laser pulses

3 by short ultraviolet laser pulses (0.5 ps, 248 nm) is presented. Gratings with a period of 360 nm and a modulation depth of 80 nm are fabricated on the sample surface by single-laser-shot exposure. The structures are projection imaged by a Schwarzschild objective in air. The modulation depth can be varied by applying multiple-pulse exposure. Received: 18 July 1997/Accepted: 5 August 1997     

Fabrication of silicon nanowires

2 at 750 °C and 850 °C. The oxide and interface morphology are characterized by cross-sectional scanning electron microscope images. It is found that the oxidized nanowire following oxidation at 750 °C still keeps its pentagon shape even if it has been oxidized for 19 h. However, the oxidized samples at 850 °C become circular in shape. The oxidation-temperature dependence of the sample shapes is discussed. Our results should be useful in generating silicon nanowires coated with SiO₂ in microelectronic technology with careful selection of the SiO₂ growth temperatures. Received: 26 September 1997/Accepted: 8 December 1997     

Excimer laser ablation of thin gold films on a quartz crystal microbalance at various argon background pressures

Received: 21 June 1996/Accepted: 9 December 1996     

Characteristics of the conductive polyimide film surfaces induced by ultraviolet laser beam

-1 cm^-1 stripped in a solvent from KrF-laser-irradiated polyimide thin film is taken as a sample to determine the microstructure of the conducting layer. Fourier-transform infrared and X-ray photoelectron spectroscopies show the formation of the carbon-rich clusters after irradiation. The element analysis gives the atomic ratio of C:H:N:O for the carbon-rich cluster as 60:20:3:1. Wide-angle X-ray diffraction indicates that the conducting layer is mainly amorphous carbon with a small amount of the short-range ordered carbon-rich clusters. This study suggests a structural model with three-layer carbon sheets linked together in a random fashion for the short-range ordered carbon-rich clusters. The interplanar spacing is 3.87 Å and the layer diameter 25 Å. The transport model of variable-range hopping in three dimensions is used to explain the conducting behavior of the conducting layer. In our case, the short-range ordered carbon-rich clusters are assumed to be conducting islands dispersed in the amorphous carbon-rich cluster matrix. Received: 26 May 1997/Accepted: 8 September 1997     

Bubble nucleation and pressure generation during laser cleaning of surfaces

with a pressure pulse width of . Additionally, the phase of an acoustic pulse is observed to change upon reflection at the liquid–solid interface if bubbles are present, providing a direct proof for laser-induced bubbles. Received: 5 December 1996/Accepted: 6 January 1997     

High-speed machining of glass materials by laser-induced plasma-assisted ablation using a 532-nm laser

+ :YAG laser (532 nm). The plasma generated from a silver (Ag) target by the laser irradiation effectively assists in ablation of the fused quartz substrate by the same laser beam, although the laser beam is transparent to the substrate. A grating with a cross-sectional shape like a square-wave (period ≈ 20 μm) is achieved using the mask projection technique. The ablation rate reaches several tens nm/pulse. In addition, LIPAA is applied to high-speed hole drilling (700 μm in diameter) of fused-quartz (0.5 mm thick) and Pyrex glass (0.5 mm thick). Received: 25 May 1998/Accepted: 19 June 1998     

Absorption and saturation mechanisms in aluminium laser ablated plasmas

-2 ). The interpretation of the ion TOF distributions in terms of theoretical shifted Maxwell–Boltzmann distributions produces a good agreement with the experimental data. This has allowed us to infer the ion flow velocity and temperature associated with the measured TOF distributions, as well as the ion kinetic energies as a function of the laser fluence. We have also studied the total ion yield at different laser fluences. Our results show that all the plume parameters investigated are increasing functions of the laser fluence until a saturation plateau is reached at high fluences (>20 Jcm^-2). We ascribe this saturation behav iour to strong absorption and partial, or total, reflection of the laser light by the hot plasma produced by the leading edge of the intense laser pulse. This interpretation is supported by a semi-quantitative analysis of the laser photon absorption and ionization mechanisms in Al plasma, at both laser wavelengths. Received: 6 January 1997/Accepted: 14 March 1997     

Heat diffusion and debris screening in Er:YAG laser ablation of hard biological tissues

Received: 25 March 1997/Revised version: 15 October 1997     

Laser-induced plasma-assisted ablation of fused quartz using the fourth harmonic of a Nd+:YAG laser

+ :YAG laser (266 nm) is reported. With the assistance of plasma resulting from laser irradiation on a metal target, the fused-quartz substrate is easily etched by the 266-nm laser beam in spite of the fact that the substrate is transparent to this wavelength. In contrast, no ablation takes place without the metal target, but damage is generated on the substrate surface. The ablated region is observed by optical microscopy and scanning probe microscopy (SPM), which reveal a fine grating structure (line spacing of 20 μm) without any severe damage. A series of experiments on the dependence of the ablation rate and the threshold laser fluence on ablation parameters, such as laser fluence, the number of pulses, and the distance between the fused quartz and the metal target is performed. On the basis of the results, three possible mechanisms of direct plasma interaction, plasma heating, and metal film deposition are discussed. Received: 27 February 1998/Accepted: 5 June 1998     

A theoretical model for laser removal of particles from solid surfaces

Received: 13 November 1996/Accepted: 30 January 1997     

Neurons from rat brain coupled to transistors

Received: 2 June 1997/Accepted: 3 June 1997