&lt;title&gt;Boiling process in PMMA irradiated by CO2, DF and HF laser radiations&lt;/title&gt;

Joeckle, R.; Rapp, Gerard; Sontag, Andre

doi:10.1117/12.25988

Cited by 3 publications

(4 citation statements)

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“…2, the bubbles are less than~0.02 mm in diameter. The damaged zone on the post-irradiated PMMA exhibit well defined sharp edges, confirming that there is a threshold fluence for generating bubbles only in the center of the beam [22].…”

Section: Imagerymentioning

confidence: 51%

“…In-depth absorption can lead to subsurface boiling. The size of the bubbles decreases at longer laser wavelength and higher irradiance [22]. From Fig.…”

Section: Imagerymentioning

confidence: 91%

“…The absorptivity of clear PMMA varies depending on the type of laser wavelength used, a value of 250 cm À1 was obtained with a CO 2 laser (10.6 mm), whereas values of~25 cm À1 were assumed for hydrogen fluoride (HF) and deuterium fluoride (DF) chemical lasers with wavelengths of 2.7 mm and 3.8 mm respectively [22]. When thermoplastic polymers were irradiated with a CO 2 laser, Cozzens and Fox [23] reported that minimal decomposition occurred between 3 and 7 W/cm 2 , but at 5e11 W/cm 2 softening was observed.…”

Section: Introductionmentioning

confidence: 99%

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Thermal degradation of Poly(methyl methacrylate) with a 1.064 μm Nd:YAG laser in a buoyant flow

Acosta

Gross

Perram

2015

Polymer Degradation and Stability

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Section: Imagerymentioning

confidence: 51%

“…In-depth absorption can lead to subsurface boiling. The size of the bubbles decreases at longer laser wavelength and higher irradiance [22]. From Fig.…”

Section: Imagerymentioning

confidence: 91%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Thermal degradation of Poly(methyl methacrylate) with a 1.064 μm Nd:YAG laser in a buoyant flow

Acosta

Gross

Perram

2015

Polymer Degradation and Stability

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“…On Plexiglass (PMMA), it has been shown [4] that this absorption depth results in a boiling process in the material : due to the in-depth heating, the decomposition of the polymer occurs not only at the free surface, but also in-depth : bubbles can be observed during the irradiation. At the end of the irradiation, the material cools down rapidly, the viscosity increases fast and several bubbles remain trapped under the surface.…”

Section: Champions (Co2 and Nd:yag) And Challengers (Co And Hf)mentioning

confidence: 99%

Influence of the wavelength for infrared laser effects on metals and dielectrics

Joeckle¹,

Stevens

Stern³

et al. 1994

SPIE Proceedings

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Two high power mid-JR gas lasers, the CO laser and the chemical HF laser, can offer higher absorption for metals and better focusing, i.e. smaller spot areas than CO2 and Nd:YAG lasers. A comparison ofthe effects of three gas lasers is carried out at the ISL, using three high-power gas lasers : 1 kW (HF), 6 kW (CO) and 7.5 kW (C02) and allows to compare their effects on different materials.The absorptivity of these laser beams for several metals has been measured, both th low energy measurement techniques and with high power laser beams; an increase in absorptivity has been demonstrated for the short wavelengths lasers.Plexiglass irradiated with these lasers beams exhibits a boiling-type destruction behaviour. The threshold fluence for the occurence of the bubbles has been measured and compared with a simple boiling model showing the importance ofthe spectral absorption coefficient.High power lasers have been developed in the CEI and (for industrial applications) in Japan and in Germany. Cooling of the laser gas is obtained, either cryogenic using a liquid nitrogen heat exchanger or by O19413763194'$6.00

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Infrared light induced degradation of polymeric materials used in optical devices

Osenbach¹,

Jack²,

Singh³

et al.

2004 Proceedings. 54th Electronic Components and Technology Conference (IEEE Cat. No.04CH37546)

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The paper summarizes the current understanding of laserinduced damage in polymeric material systems. A detailed literature review including macroscopic and microscopic models for high optical intensity induced degradation and damage of polymeric systems is given. This is followed with experimental results and discussion on degradation of two different commonly used polymeric systems (acrylic and epoxy) due to exposure to medium optical intensity infrared light. We show that in acrylic systems, degradation occurs slowly over time at infrared wavelengths as high as 1480nm and optical power densities as low as 5X104 W/cm2. In this syaem degradation occurs via a multi-photon absorption pro:ess. In cases where no catastrophic damage occurs, it is possible to completely and repeatedly anneal out any optically induced changes in the acrylic systems. The recovery process for these systems oc&-s via a 1.7 eV process. Moisture appears to accelerate !the degradation rate in these systems. We show that in bisphenol based epoxy systems (bisphenol baxd epoxies are widely used as structural adhesives in many opt1 cal devices), degradation also occurs via a multi-photon absorption process. In all cases, degradation in the bisphenol sysl ems was catastrophic. The time dependent degradation data for this epoxy system indicates that a three-photon absorption process is responsible for degradation in these epoxies. Therefore, the degradation process is very sensitive to both wavelength and optical power density. We did not observe degradation after hundreds of hours of exposure to optical power densities as high at 6MW/cm2 at 1480nm between 25C and 175C in this material system. Degradation was observed in less than 10 hours when the material was exposed to 6MW/cm2 optical power at 1060nm at room temperature. We find the degradation is thermally accelerated with an effective activation energy of > 0.5eV. Finally, we give preliminary design guidelines for the use of bisphenolbased epoxies in high optical power density applications. I IintroductionMany polymeric systems exhibit good transparency in the near infrared region of the electromagnetic spectrum that is of greiit importance in the telecommunications and data communication industry, approximately 800nm to 1650nm. Typical hydrocarbon based systems have a linear absorption betmeen 1 and 4dB/cm in the 1000nm-1600nm region of the electromagnetic spectrum. This absorption is primarily due to C-E[ stretching (v -1720 nm) and stretching and deformation overtones (v -1350-1500 nm) and 0-H stretching overtones (v .-+ 1430 nm).' Because these materials have losses that are greater than ldB/cm in this region of the spectrum, they are not readily used to transmit light over long distances in the wat elength region. However, in many applications these mat1:rials are used in thin joint configurations, where the joint I thickness is less than 100 pm (typically the actual joint thickness is 10-30 pm). In this configuration the loss per joint is less than 0.04dE3 (4% signal loss). In addition, ...

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<title>Boiling process in PMMA irradiated by CO2, DF and HF laser radiations</title>

Cited by 3 publications

References 1 publication

Thermal degradation of Poly(methyl methacrylate) with a 1.064 μm Nd:YAG laser in a buoyant flow

Thermal degradation of Poly(methyl methacrylate) with a 1.064 μm Nd:YAG laser in a buoyant flow

Influence of the wavelength for infrared laser effects on metals and dielectrics

Infrared light induced degradation of polymeric materials used in optical devices

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