Development of large area input “shadowers” with intricate geometries for growth-suppression of exit surface damage on fused silica

2021 ◽  
Author(s):  
Eyal Feigenbaum ◽  
Isaac L. Bass ◽  
James L. Vickers ◽  
Gabe Guss ◽  
Christopher W. Carr
Keyword(s):  
Surface Damage ◽  
Growth Suppression ◽  
Fused Silica ◽  
Large Area ◽  
Exit Surface

Fracture of fused silica with 351 nm laser-generated surface cracks

1999 ◽  
Vol 14 (2) ◽  
pp. 597-605 ◽  
Author(s):  
F. Dahmani ◽  
J. C. Lambropoulos ◽  
A. W. Schmid ◽  
S. Papernov ◽  
S. J. Burns
Keyword(s):  
Crack Depth ◽  
Damage Threshold ◽  
Surface Damage ◽  
Laser Pulses ◽  
Fused Silica ◽  
Material Strength ◽  
Failure Strength ◽  
Exit Surface ◽  
Four Point Bending ◽  
Underlying Basis

Laser-induced-surface-flaw experiments on fused silica at 351 nm and 500 ps pulse duration are reported here. Specimens with surface flaws produced at a measured exit-surface damage threshold fluence of Fexit/th = 10 J/cm2 were irradiated at a constant fluence of FL = 1.8 × Fexit/th by different numbers of laser pulses, N = 110 to 520. Micrograph observations show that (i) the produced cracks have a semielliptical shape and (ii) the material strength predictions based on the radial crack depth (normal to the surface) instead of the crack surface length (parallel to the surface) are in good agreement with measured strengths obtained using a four-point bending fixture. The underlying basis of conventional crack analysis is first examined critically and is argued to be deficient in the way the failure strength for the cracks is related to the characteristic parameters of crack geometry. In general, it is necessary to incorporate a residual term into the failure strength formulation. The crack depth and the failure strength are found to increase and decrease with the number of laser pulses, respectively.

Study of the effects of stress wave behavior in laser-induced exit-surface damage of fused silica using time-resolved multi-polariscopic imaging

2021 ◽  
Vol 33 (2) ◽  
pp. 022018
Author(s):  
Lingxi Liang ◽  
Chengyu Zhu ◽  
Hang Yuan ◽  
Luoxian Zhou ◽  
Yuxin Li ◽  
...  
Keyword(s):  
Stress Wave ◽  
Surface Damage ◽  
Fused Silica ◽  
Time Resolved ◽  
Exit Surface ◽  
Effects Of Stress

Study of Tip-Surface Interactions in Scanning Tunneling Microscopy (STM) by Reflection Electron Microscopy (REM)

1990 ◽  
Vol 48 (1) ◽  
pp. 320-321
Author(s):  
W. Lo ◽  
J.C.H. Spence ◽  
M. Kuwabara
Keyword(s):  
High Resolution ◽  
Elastic Strain ◽  
Tunneling Current ◽  
Surface Damage ◽  
Surface Interactions ◽  
Graphite Surface ◽  
Scanning Tunneling ◽  
Large Area ◽  
Tunneling Microscopy ◽  
High Resolution Tem

Work on the integration of STM with REM has demonstrated the usefulness of this combination. The STM has been designed to replace the side entry holder of a commercial Philips 400T TEM. It allows simultaneous REM imaging of the tip/sample region of the STM (see fig. 1). The REM technique offers nigh sensitivity to strain (<10−4) through diffraction contrast and high resolution (<lnm) along the unforeshortened direction. It is an ideal technique to use for studying tip/surface interactions in STM.The elastic strain associated with tunnelling was first imaged on cleaved, highly doped (S doped, 5 × 1018cm-3) InP(110). The tip and surface damage observed provided strong evidence that the strain was caused by tip/surface contact, most likely through an insulating adsorbate layer. This is consistent with the picture that tunnelling in air, liquid or ordinary vacuum (such as in a TEM) occurs through a layer of contamination. The tip, under servo control, must compress the insulating contamination layer in order to get close enough to the sample to tunnel. The contaminant thereby transmits the stress to the sample. Elastic strain while tunnelling from graphite has been detected by others, but never directly imaged before. Recent results using the STM/REM combination has yielded the first direct evidence of strain while tunnelling from graphite. Figure 2 shows a graphite surface elastically strained by the STM tip while tunnelling (It=3nA, Vtip=−20mV). Video images of other graphite surfaces show a reversible strain feature following the tip as it is scanned. The elastic strain field is sometimes seen to extend hundreds of nanometers from the tip. Also commonly observed while tunnelling from graphite is an increase in the RHEED intensity of the scanned region (see fig.3). Debris is seen on the tip and along the left edges of the brightened scan region of figure 4, suggesting that tip abrasion of the surface has occurred. High resolution TEM images of other tips show what appear to be attached graphite flakes. The removal of contamination, possibly along with the top few layers of graphite, seems a likely explanation for the observed increase in RHEED reflectivity. These results are not inconsistent with the “sliding planes” model of tunnelling on graphite“. Here, it was proposed that the force due to the tunnelling probe acts over a large area, causing shear of the graphite planes when the tip is scanned. The tunneling current is then modulated as the planes of graphite slide in and out of registry. The possiblity of true vacuum tunnelling from the cleaned graphite surface has not been ruled out. STM work function measurements are needed to test this.

scholarly journals Effect of Rogue Particles on the Sub-Surface Damage of Fused Silica during Grinding/Polishing

2006 ◽  
Author(s):  
Tayyab Suratwala ◽  
R. Steele ◽  
M. D. Feit ◽  
L. Wong ◽  
P. Miller ◽  
...  
Keyword(s):  
Surface Damage ◽  
Fused Silica

Influence of vacuum on nanosecond laser-induced surface damage morphology in fused silica at 1064 nm

2016 ◽  
Vol 362 ◽  
pp. 290-296 ◽  
Author(s):  
R. Diaz ◽  
M. Chambonneau ◽  
P. Grua ◽  
J.-L. Rullier ◽  
J.-Y. Natoli ◽  
...  
Keyword(s):  
Surface Damage ◽  
Fused Silica ◽  
Nanosecond Laser ◽  
Damage Morphology
Sign in / Sign up

Export Citation Format

Share Document