Micro‐Shaping, Polishing, and Damage Repair of Fused Silica Surfaces Using Focused Infrared Laser Beams

Matthews, Manyalibo J.; Yang, S. T.; Shen, Nan; Elhadj, Selim; Raman, Rajesh N.; Guss, Gabe; Bass, Isaac L.; Nostrand, Michael C.; Wegner, Paul J.

doi:10.1002/adem.201400349

Cited by 63 publications

(20 citation statements)

References 17 publications

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“…COMSOL Multiphysics software was used to simulate the temperature distribution of the chip when the laser is continuously illuminated, as shown in Figure S1 in the Supporting Information. Since the laser is axisymmetric and the power follows a Gaussian distribution, the input power density ( Q ) of each point in the laser spot is related to its position as

Q = \frac{P η_{normalA}}{2 π R^{2}} \exp (- \frac{r^{2}}{2 R^{2}})

where r is the distance from the spot center and R is the spot radius. The absorbing layer was very thin and was regarded as a plane.…”

Section: Resultsmentioning

confidence: 99%

2D to 3D Manipulation and Assembly of Microstructures Using Optothermally Generated Surface Bubble Microrobots

Dai

Jiao

et al. 2019

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Hydrogel microstructures that encapsulate cells can be assembled into tissues and have broad applications in biology and medicine. However, 3D posture control for a single arbitrary microstructure remains a challenge. A novel 3D manipulation and assembly technique based on optothermally generated bubble robots is proposed. The generation, rate of growth, and motion of a microbubble robot can be controlled by modulating the power of a laser focused on the interface between the substrate and a fluid. In addition to 2D operations, bubble robots are able to perform 3D manipulations. The 3D properties of hydrogel microstructures are adjusted arbitrarily, and convex and concave structures with different heights are designed. Furthermore, annular micromodules are assembled into 3D constructs, including tubular and concentric constructs. A variety of hydrogel microstructures of different sizes and shapes are operated and assembled in both 2D and 3D conformations by bubble robots. The manipulation and assembly methods are simple, rapid, versatile, and can be used for fabricating tissue constructs.

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Q = \frac{P η_{normalA}}{2 π R^{2}} \exp (- \frac{r^{2}}{2 R^{2}})

where r is the distance from the spot center and R is the spot radius. The absorbing layer was very thin and was regarded as a plane.…”

Section: Resultsmentioning

confidence: 99%

2D to 3D Manipulation and Assembly of Microstructures Using Optothermally Generated Surface Bubble Microrobots

Dai

Jiao

et al. 2019

Small

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“…According to Matthews et al, the laser damage threshold increases with CO 2 laser treatment of large optics. 8 Choi et al produced microlens arrays by polishing gratings. 9 Further fundamental studies of different research groups show the increasing relevance of laser polishing process of glass.…”

Section: State Of the Artmentioning

confidence: 99%

Laser polishing and laser shape correction of optical glass

Weingarten

Schmickler

Willenborg

et al. 2017

Journal of Laser Applications

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Mechanical polishing of glass is a time consuming process especially for lenses deviating from spherical surface such as aspheres. With laser polishing, the processing time can be significantly reduced and the wear of hard tooling can be avoided. Using laser radiation for polishing, a thin surface layer of the glass is heated up just below evaporation temperature due to the interaction of glass material and laser radiation. With increasing temperature, the reduced viscosity in the surface layer leads to the reduction of the roughness due to the surface tension. Hence, a contactless polishing method can be realized nearly without any loss of material or need of polishing agent. In this paper, results for laser polishing of fused silica, BK7, and S-TIH6 are presented with area rates up to 5 cm2/s. However, the results show that the achieved roughness with laser polishing is strongly influenced by the thermal properties of the type of glass. During laser polishing, the glass material is relocated at the surface, thus no shape errors can be corrected. To reduce the residual waviness and shape errors after laser polishing, the authors investigated a further laser-based process step (laser beam figuring, LBF) which ablates material for a shape correction. Ablation depths <5 nm allow a high precision laser ablation for selective processing. For both processes, a CO2 laser is used

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“…Over the past few years, one of the development directions of optical elements tends to be miniaturized and diversified, requiring higher surface quality and more complex shapes [1][2][3] . Laser polishing as a novel economic and time-saving technique has demonstrated the ability to reduce the surface roughness and cause no surface/ subsurface damages [4][5][6] . Researches have investigated laser polishing of glass, including flat, spherical, and aspherical surface shapes with a continuous wave (CW) CO 2 laser.…”

mentioning

confidence: 99%

Numerical model and experimental demonstration of high precision ablation of pulse CO2 laser

Wei

Jiang

et al. 2018

Chin. Opt. Lett.

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To reveal the physical mechanism of laser ablation and establish the prediction model for figuring the surface of fused silica, a multi-physical transient numerical model coupled with heat transfer and fluid flow was developed under pulsed CO 2 laser irradiation. The model employed various heat transfer and hydrodynamic boundary and thermomechanical properties for assisting the understanding of the contributions of Marangoni convention, gravitational force, vaporization recoil pressure, and capillary force in the process of laser ablation and better prediction of laser processing. Simulation results indicated that the vaporization recoil pressure dominated the formation of the final ablation profile. The ablation depth increased exponentially with pulse duration and linearly with laser energy after homogenous evaporation. The model was validated by experimental data of pulse CO 2 laser ablation of fused silica. To further investigate laser beam figuring, local ablation by varying the overlap rate and laser energy was conducted, achieving down to 4 nm homogenous ablation depth.

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Micro‐Shaping, Polishing, and Damage Repair of Fused Silica Surfaces Using Focused Infrared Laser Beams

Cited by 63 publications

References 17 publications

2D to 3D Manipulation and Assembly of Microstructures Using Optothermally Generated Surface Bubble Microrobots

2D to 3D Manipulation and Assembly of Microstructures Using Optothermally Generated Surface Bubble Microrobots

Laser polishing and laser shape correction of optical glass

Numerical model and experimental demonstration of high precision ablation of pulse CO2 laser

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