Hardness, elastic modulus, and fracture toughness bulk properties in Corning calcium fluoride

Ladison, Julie L.; Price, James J.; Helfinstine, J. D.; Rosch, W.

doi:10.1117/12.601033

Cited by 13 publications

(8 citation statements)

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“…13,20 The crystallographically conditioned anisotropy in hardness and material removal mechanisms of the CaF 2 single crystal leads to the anisotropy of stored energy and damage type. 7,9,11 In the regions of ductile deformation, damage is represented by dislocations and the dislocation density decreases toward the regions of brittle deformation, where cleavage microcracks prevail.…”

Section: Discussionmentioning

confidence: 99%

“…The anisotropy of the chemical-mechanical properties of a CaF 2 single crystal leads to different removal rates in certain parts of the processed surface and to the formation of a characteristic surface shape distortion with highs and lows varying periodically at 120 deg (Fig. 1), 6,7 which it is difficult to subsequently minimize without CNC subaperture correction polishing.…”

Section: Introductionmentioning

confidence: 99%

“…CaF 2 is a soft and brittle material that exhibits crystalline anisotropy causing variation in the hardness and Young's modulus of the machined surface 7 as well as stored residual stress, 8 which leads to changes in the material deformation and removal mechanism depending on the orientation of the CaF 2 crystal lattice and contact stress during surface processing. [9][10][11] The CaF 2 crystal anisotropy thus causes transition between ductile and brittle modes of material removal during the processing of (a)spherical shapes made of CaF 2 (111).…”

Section: Introductionmentioning

confidence: 99%

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Minimization of CaF2 spherical surface deformation caused by annealing

et al. 2021

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Minimization of CaF2 spherical surface deformation caused by annealing

et al. 2021

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“…Third, even if the thermal properties are relatively good for an Yb-doped material, some issues still have to be considered for high power applications. Since the fluorite is a soft material [50] (compared to oxides for example) the specificities of the laser crystal mounting and efficient interfacing with heat sinks are very critical in order to avoid excessive stresses. Indeed, it is demonstrated that stresses in fluorite induce birefringence effects [51] due to elastic anisotropy.…”

Section: B Drawbacksmentioning

confidence: 99%

High Repetition Rate Yb:CaF<sub>2</sub> Multipass Amplifiers Operating in the 100-<roman>mJ</roman> Range

Papadopoulos

Friebel

Pellégrina

et al. 2015

IEEE J. Select. Topics Quantum Electron.

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We present the research advances on the development of 50-200 mJ energy range diode-pumped Yb:CaF 2based multipass amplifiers operating at relatively high repetition rates. These laser amplifiers are based on diverse innovative geometries. All these innovations aim to design compact, stable and reliable amplifiers adapted to our application that consists in pumping ultrashort-pulse OPCPA (optical parametric chirped pulse amplifier) systems in the frame of the Apollon 10 PW laser project. The targeted repetition rate is in the range of 20-100 Hz with energies of few tens of mJ for the first stages up to 1 J for the final stage. An analysis of the specificities of Yb:CaF 2 is done to explain the different options we chose to fulfil these specifications. The critical points and limitations of the multipass Yb:CaF 2-based amplifiers are subsequently discussed. To overcome the encountered problems, different issues are investigated such as crystal optimisation, laser head geometry, thermo-optical dynamics or coherent combining techniques. Experimental results for different multipass configurations are demonstrated and discussed.

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“…In fact, its Knoop hardness and fracture toughness are ~163 kg mm −2 and ~0.3 MPa m 1/2 while those of glass (soda-lime) and silicon are ~500 kg mm −2 and 0.8 MPa m 1/2 , and ~1100 kg mm −2 and 0.9 MPa m 1/2 respectively. [28][29][30] Moreover, the thermal expansion of CaF 2 is about six times larger than that of silicon, whereas the thermal conductivity is more than ten times smaller, which means that it suffers larger thermal stresses.…”

Section: Introductionmentioning

confidence: 99%

SU-8 bonding protocol for the fabrication of microfluidic devices dedicated to FTIR microspectroscopy of live cells

et al. 2014

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Here we present a new bonding protocol for SU-8 negative tone photoresist that exploits the chemical modifications induced in the resin by exposure to 254 nm (UVC) light. Fourier Transform Infrared microspectroscopy (μ-FTIR) was used to carry out a thorough study on the chemical processes and modifications occurring within the epoxy resin by exposure to 365 nm and 254 nm light. In particular, we established that UVC light promotes the opening of the epoxy rings bypassing the post-exposure bake. The possibility to promote a further activation of the resin, already patterned with standard UV lithography, was exploited to produce closed microfluidic devices. Specifically, we were able to fabricate fluidic chips, characterized by broadband transparency from mid-IR to UV and long term stability in continuous flow conditions. CaF2 was used as substrate, coated by sputtering with a nanometric silicon film, in order to make surface properties of this material more suitable for standard fabrication processes with respect to the original substrate. The fabricated microfluidic chips were used to study by μ-FTIR the biochemical response of live breast cancer MCF-7 cells to osmotic stress and their subsequent lysis induced by the injection of deionized water in the device. μ-FTIR analyses detected fast changes in protein, lipid and nucleic acid content as well as cytosol acidification.

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Hardness, elastic modulus, and fracture toughness bulk properties in Corning calcium fluoride

Cited by 13 publications

References 0 publications

Minimization of CaF2 spherical surface deformation caused by annealing

Minimization of CaF2 spherical surface deformation caused by annealing

High Repetition Rate Yb:CaF<sub>2</sub> Multipass Amplifiers Operating in the 100-<roman>mJ</roman> Range

SU-8 bonding protocol for the fabrication of microfluidic devices dedicated to FTIR microspectroscopy of live cells

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