Traceless mitigation of laser damage precursors on a fused silica surface by combining reactive ion beam etching with dynamic chemical etching

Abstract

RIBE and DCE techniques can be combined to tracelessly mitigate laser damage precursors on a fused silica surface.

Understanding the effect of HF-based wet shallow etching on optical performance of reactive-ion-etched fused silica optics

“…3 shows the relationship between the laser fluence and the 1-on-1 damage probability of the samples. Similarly to in our previous work, 23,25 the damage threshold of the combined etched surface was much higher than that of the unetched surface. This great improvement was attributed to the effective removal of the subsurface damage layer, which contains abrasive residues and other polishing-induced contaminants.…”

“…The damage tests of the fused silica samples prepared using our combined RIE and DCE processes were performed using a Q-switched Nd:YAG laser operating at 355 nm. Unlike the damage test system used in our previous study, 23 this system uses a relatively small-area laser beam focused at the exit surface (around 0.25 mm in diameter) to ensure that all the etched surfaces can be laser-damaged within the available laser fluence range. The temporal profile of the laser beam was near-Gaussian with a full width at half max pulse duration of approximately 5 ns.…”

“…The experimental setup for RIE can be found elsewhere. 23 The RIE-pretreated samples were then treated again using dynamic cleaning and an HF-based chemical etching technique (described as DCE in our previous study 22 ). Two sets of three samples were treated with different HF-based etching depths (1 mm, 2 mm, and 3 mm, respectively), as summarized in Fig.…”

Study on Damage Characteristics of Fused Silica under Ion Beam Sputtering and AMP Technique

“…Shao found AMP technique can remove chemical structure defects (ODC/NBOC) introduced in prepolishing process and effectively improve laser damage threshold of fused silica optics [17]. Sun also found AMP can remove Ce or other polluting elements, and the damage threshold of fused silica optics even reached 20 J/cm 2 [18].…”

Study on the Absorption Characteristics and Laser Damage Properties of Fused Silica Optics under Flexible Polishing and Shallow DCE Process

“…Shao Ting found that a deep DCE technique could remove chemical structure defects (oxygen deficit center (ODC)/non-bridging oxygen hole center (NBOHC) formed in RIE process [ 11 ]. Sun Laixi also found that RIE combined with deep DCE technique could effectively remove kinds of micro defects [ 12 ]. After removing several microns of materials, not only the Ce element introduced by traditional grinding process was removed, but also the impurity ions introduced in RIE process were obviously controlled.…”