Femtosecond Pulsed Laser-Induced Micromachining of Difficult-to-Machine Materials: Diamond a Case Study

2000 ◽  
Author(s):  
A. P. Malshe ◽  
A. M. Ozkan ◽  
T. A. Railkar ◽  
K. P. Adhi ◽  
W. D. Brown ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Excimer Laser ◽  
Etching Rate ◽  
Polycrystalline Diamond ◽  
Single Pulse ◽  
Laser Wavelength ◽  
Diamond Surface ◽  
Single Shot ◽  
Micro Machining ◽  
3 Dimensional

Abstract Meso and micro scale machining is an important and emerging area of research. Various non-traditional and novel tools are being explored for meso and micro machining of non-silicon materials. In this paper, we report etching, micro machining and related phenomena of commercially available single and polycrystalline diamond using a femtosecond pulsed excimer laser (λ = 248 nm, tp ∼ 380 fs). Surface modifications due to single pulse and multiple pulse irradiation of diamond samples, at different energy densities, have been analyzed using Raman spectroscopy, scanning electron microscopy (SEM) and atomic force microscopy (AFM). Etching rate of single crystal type IIA diamond by femtosecond pulsed excimer laser is also studied. Raman spectroscopy study of the single shot irradiation of diamond with a femto second laser shows the formation of a non-diamond disordered (sp2 bonded) phase on the surface. However, subsequent micro machining of this non-diamond disordered surface, by delivering several shots from the femtosecond laser, results in the removal of the non-diamond disordered layer and the restoration of the diamond surface. It is experimentally shown that the periodicity of the 2-dimensional corrugations written on diamond surface is shorter than the laser wavelength used. 3-dimensional writing on diamond globules during laser etching is also discussed. Further, micro machining of diamond tips is shown to be precise, and without mechanical and chemical damages. Femto second laser is demonstrated as a next-generation tool for mechanical and chemical damage free precision micro machining of the hardest material, diamond.

CRACKING AND EXFOLIATION OF TiO2 FILM IRRADIATED WITH EXCIMER LASER

2008 ◽  
Vol 15 (04) ◽  
pp. 473-479 ◽  
Author(s):  
H. X. QIAN ◽  
W. ZHOU ◽  
H. Y. ZHENG
Keyword(s):  
Excimer Laser ◽  
Laser Fluence ◽  
Single Pulse ◽  
Single Shot ◽  
Uv Laser ◽  
Original Surface ◽  
Excimer Laser Pulse ◽  
Surface Protrusion ◽  
Krf Excimer Laser ◽  
Effect Of Surface

TiO 2 film deposited on glass was irradiated in air with single-shot KrF excimer laser pulse. The surface roughened as the result of the laser ablation. It is further noted that single-pulse irradiation with fluence ranging from 400 to 1200 mJ/cm2 gave rise to protrusion of the irradiated surface above the original surface, which is in contrast to usual expectation that irradiated surface is below the unirradiated surface. The surface protrusion is mainly attributed to the effect of surface tension. At the laser fluence of 1000 mJ/cm2, cracks were formed in the irradiated area and severe film exfoliation was observed at the periphery of the irradiated area due to the release of internal stress. With higher laser fluence above 1000 mJ/cm2, patches of film were observed to peel off within the irradiated areas. Hydrodynamic ablation is proposed to account for film exfoliation. The observed phenomenon is useful for further understanding how TiO 2 film reacts to strong UV laser irradiation.

Air oxidation of undoped and B-doped polycrystalline diamond films at high temperature

1996 ◽  
Vol 11 (2) ◽  
pp. 296-304 ◽  
Author(s):  
Koichi Miyata ◽  
Koji Kobashi
Keyword(s):  
High Temperature ◽  
Etching Rate ◽  
Diamond Films ◽  
Polycrystalline Diamond ◽  
Temperature Treatment ◽  
Diamond Surface ◽  
High Temperature Treatment ◽  
Air Oxidation ◽  
B Doping ◽  
Electron Energy Loss

Air oxidation of undoped and B-doped polycrystalline diamond films was investigated at temperatures between 500 and 700 °C. Diamond (111) facets were etched for both undoped and B-doped films after 1 h at 700 °C. The etching rate of (111) facet due to oxidation was approximately 50% lower by B-doping of 1 × 1019 cm−3, presumably because of the decrease of sp2 bands and lattice defects that were identified by Raman and photoluminescence spectroscopy. X-ray photoelectron and electron energy loss spectroscopy revealed that by the high temperature treatment, the diamond surface was initially converted into graphite and successively etched by oxygen.

Excimer Laser Planarization of Diamond Films

1994 ◽  
Vol 339 ◽  
Author(s):  
Dong-Gu Lee ◽  
S. D. Harkness ◽  
Rajiv K. Singh
Keyword(s):  
Energy Density ◽  
Excimer Laser ◽  
Arc Discharge ◽  
Incidence Angle ◽  
Etching Rate ◽  
Diamond Films ◽  
Threshold Energy ◽  
Diamond Surface ◽  
Threshold Energy Density ◽  
Laser Fluences

ABSTRACTThe planarization of rough polycrystalline diamond films synthesized by DC arc discharge plasma jet CVD was attempted using KrF excimer laser pulses. The effects of laser incidence angle and reaction gases (ozone and oxygen) on etching rate were studied. The temperature change of diamond and graphite with different laser fluences was calculated by computer simulation to explain the etching behavior of diamond films. The calculated threshold energy density for etching of pure crystalline diamond was about 1.7 J/cm2. However, the threshold energy density was affected by the angle of laser incidence. Preferential etching of a particular crystallographic plane was observed through scanning electron microscopy. The etching rate of diamond with ozone was lower than that with oxygen. Also, the etching rate of diamond films at normal laser incidence was lower than that of films tilted at 45° for laser fluences above 2.3 J/cm2. When the angle of incidence was 80° to the diamond surface normal, the peak-to-valley surface roughness was significantly reduced, from 30 μm to 0.5μm.

Single pulse vibrational Raman scattering by a broadband KrF excimer laser in a hydrogen–air flame

1990 ◽  
Vol 29 (15) ◽  
pp. 2325 ◽  
Author(s):  
Robert W. Pitz ◽  
Joseph A. Wehrmeyer ◽  
J. M. Bowling ◽  
Tsarng-Sheng Cheng
Keyword(s):  
Raman Scattering ◽  
Excimer Laser ◽  
Single Pulse ◽  
Krf Excimer Laser

Effect of laser radiation parameters on the conductivity of structures produced on the polycrystalline diamond surface

2017 ◽  
Vol 44 (8) ◽  
pp. 246-248 ◽  
Author(s):  
M. S. Komlenok ◽  
M. A. Dezhkina ◽  
V. V. Kononenko ◽  
A. A. Khomich ◽  
A. F. Popovich ◽  
...  
Keyword(s):  
Laser Radiation ◽  
Polycrystalline Diamond ◽  
Diamond Surface

Spectrochemical Analysis of Liquids Using Laser-Induced Plasma Emissions: Effects of Laser Wavelength

1997 ◽  
Vol 51 (1) ◽  
pp. 87-91 ◽  
Author(s):  
W. F. Ho ◽  
C. W. Ng ◽  
N. H. Cheung
Keyword(s):  
Laser Pulse ◽  
Signal To Noise Ratio ◽  
Laser Wavelength ◽  
Spectrochemical Analysis ◽  
Liquid Jets ◽  
Single Shot ◽  
Transient Nature ◽  
Vapor Plume ◽  
193 Nm ◽  
532 Nm

The plasma plume emissions produced by pulsed (∼ 10 ns) laser ablation of liquid jets were monitored for spectrochemical analysis. Laser wavelengths at 532 and 193 nm were used, and sodium was the test analyte. As expected, the 532-nm laser pulse produced very intense plasma continuum emissions that masked the sodium signal for the first hundred nanoseconds, especially near the bright core of the vapor plume. Neither time-gating nor spatial masking could significantly improve the single-shot signal-to-noise ratio, since the transient nature of the emissions placed stringent demands on timing precision while the small size of the plume required accurate mask positioning—both antithetical to the inherent instability of jet ablation. In sharp contrast, the 193-nm laser pulse produced relatively dim plasma flash but intense sodium emissions, rendering it ideal for analytical applications.

scholarly journals Control of the Longitudinal Compression and Transverse Focus of Ultrafast Electron Beam for Detecting the Transient Evolution of Materials

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 571
Author(s):  
Xintian Cai ◽  
Zhen Wang ◽  
Chaoyue Ji ◽  
Xuan Wang ◽  
Zhiyin Gan ◽  
...  
Keyword(s):  
Electron Beam ◽  
Temporal Resolution ◽  
Fast Electron ◽  
Single Pulse ◽  
Coulomb Force ◽  
Single Shot ◽  
Longitudinal Compression ◽  
Rf Cavity ◽  
Tracking Model ◽  
The Impact

Ultrafast detection is an effective method to reveal the transient evolution mechanism of materials. Compared with ultra-fast X-ray diffraction (XRD), the ultra-fast electron beam is increasingly adopted because the larger scattering cross-section is less harmful to the sample. The keV single-shot ultra-fast electron imaging system has been widely used with its compact structure and easy integration. To achieve both the single pulse imaging and the ultra-high temporal resolution, magnetic lenses are typically used for transverse focus to increase signal strength, while radio frequency (RF) cavities are generally utilized for longitudinal compression to improve temporal resolution. However, the detection signal is relatively weak due to the Coulomb force between electrons. Moreover, the effect of RF compression on the transverse focus is usually ignored. We established a particle tracking model to simulate the electron pulse propagation based on the 1-D fluid equation and the 2-D mean-field equation. Under considering the relativity effect and Coulomb force, the impact of RF compression on the transverse focus was studied by solving the fifth-order Rung–Kutta equation. The results show that the RF cavity is not only a key component of longitudinal compression but also affects the transverse focusing. While the effect of transverse focus on longitudinal duration is negligible. By adjusting the position and compression strength of the RF cavity, the beam spot radius can be reduced from 100 μm to 30 μm under the simulation conditions in this paper. When the number of single pulse electrons remains constant, the electrons density incident on the sample could be increased from 3.18×1012 m−2 to 3.54×1013 m−2, which is 11 times the original. The larger the electron density incident on the sample, the greater the signal intensity, which is more conducive to detecting the transient evolution of the material.

Ablation efficiency of gold at fs/ps laser treatment in water and air

2022 ◽  
Vol 19 (2) ◽  
pp. 026001
Author(s):  
N A Smirnov ◽  
S I Kudryashov ◽  
А А Rudenko ◽  
A A Nastulyavichus ◽  
A A Ionin
Keyword(s):  
Single Pulse ◽  
Scanning Force Microscopy ◽  
Sample Surface ◽  
Spot Size ◽  
Single Shot ◽  
Gold Target ◽  
Ablation Efficiency ◽  
Significant Difference ◽  
Scanning Force ◽  
Crater Morphology

Abstract A comparison of single-pulse laser ablation of gold target by pulses with a 0.3–10 ps duration and a wavelength of 515 nm in air and in water was performed. The radiation was focused on the sample surface through the objectives with numerical apertures NA = 0.65 and 0.25. The influence of the medium, pulse duration, and spot size on the crater morphology was studied. A significant difference in crater morphology was found for different lenses. The ablation efficiency was studied by measuring the profiles of single-shot pulse craters using scanning force microscopy. The contribution of filamentation to the ablation process is shown quantitatively.

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