Lambert Absorption Coefficients of Water in the Infrared*

Robertson, Charles W.; Williams, D. R.

doi:10.1364/josa.61.001316

Cited by 154 publications

(59 citation statements)

References 5 publications

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“…Light of this wavelength is also absorbed well by enamel. [12][13][14] Enamel consists of 85% mineral by volume. The remaining 15% consists of free water and equal amounts of protein and lipid.…”

Section: Discussionmentioning

confidence: 99%

“…[7][8][9][10][11] The Er:YAG laser is able to handle dental hard tissue with high efficiency because of the high absorbability of the 2.94 m wavelength by water and dental enamel. [12][13][14] The absorbed laser energy is converted to heat that boils water in the tooth, forming high-pressure steam. The successive explosive vaporization of water modifies the smooth tooth surface, creating an irregularly serrated and microfissured morphology.…”

Section: Introductionmentioning

confidence: 99%

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Acid Resistance of Erbium-doped Yttrium Aluminum Garnet Laser–Treated and Phosphoric Acid–Etched Enamels

Kim¹,

Kwon

Kim

et al. 2006

The Angle Orthodontist

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Objective:To compare the effects of erbium-doped yttrium aluminum garnet (Er:YAG) laser ablation and of phosphoric acid etching on the in vitro acid resistance of bovine enamel. Materials and Methods: Teeth were polished to make the surface flat. The polished enamel was either etched with 37% phosphoric acid for 30 seconds or ablated with a single 33 J/cm 2 pulse from an Er:YAG laser. The control specimens were free from acid etching and laser ablation. Changes in crystal structure, dissolved mineral (calcium [Ca] and phosphorus [P]) contents, and calcium distribution in the enamel subsurface after a pH-cycling process were evaluated. Results: After laser treatment, poor crystal structures improved without forming any new phases, such as tricalcium phosphates. Among the tested enamels, dissolved mineral contents were significantly different (P Ͻ .05). Er:YAG laser-treated enamels had the lowest mineral dissolution (Ca, 13.78 ppm; P, 6.33 ppm), whereas phosphoric acid-etched enamels had the highest (Ca, 15.90 ppm; P, 7.33 ppm). The reduction rate and reduced depth of calcium content along the subsurface were lowest in Er:YAG laser-treated enamels. Conclusion:The Er:YAG laser-treated enamels are more acid resistant to acid attack than phosphoric acid-etched enamels.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Acid Resistance of Erbium-doped Yttrium Aluminum Garnet Laser–Treated and Phosphoric Acid–Etched Enamels

Kim¹,

Kwon

Kim

et al. 2006

The Angle Orthodontist

View full text Add to dashboard Cite

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“…[21] These equilibrium concentrations of H 2 O in ambient air at 60% RH are thus about a factor of ten larger than that of pure O 2 in regio-irregular P3HT (1.2 Â 10 18 cm…”

Section: à3mentioning

confidence: 93%

Direct Spectroscopic Evidence for a Photodoping Mechanism in Polythiophene and Poly(bithiophene‐alt‐thienothiophene) Organic Semiconductor Thin Films Involving Oxygen and Sorbed Moisture

et al. 2009

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Fourier-transform infrared spectroscopy of two prototypical high-mobility polymer organic semiconductors (OSCs), regioregular poly(3-hexylthiophene) (rr-P3HT) and poly[2,5-bis(3-tetradecylthiophen-2-yl)thieno(3,2-b)thiophene] (PBTTT), reveals photoinduced doping that involves both oxygen and water dissolved in the polymer matrix when exposed to light. The equilibrium concentration of water at room temperature and 60% relative humidity in these films is $2 Â 10 19 cm À3, and exists primarily as monomers, with a small population of dimers and trimers. Photo-excitation in room light ultimately generates a polaron density of the order of a few 10 17 cm À3, which is sufficient to degrade the saturation and 'on-off' characteristics of organic field-effect transistors, and the dark current of organic photovoltaics. The dopant anion has been identified primarily to be hydroxide ion species. This process occurs to a smaller extent in wet nitrogen, but even less in dry oxygen, which points to a key role of the dissolved water. The relative stability of PBTTT over rr-P3HT is found to be largely kinetic in origin, attributed to its higher crystallinity (X-ray diffraction crystallinity 27% vs 21% in rr-P3HT), and shorter pÁÁÁp stacking distance (3.64 Å vs 3.78 Å in rr-P3HT), which gives better moisture exclusion from its thiophene backbone.Understanding the degradation mechanisms of polymer organic semiconductor (OSC) devices is an essential step to develop more robust OSC systems and their devices, whether in light-emitting diodes (LEDs), field-effect transistors (FETs), or photovoltaics (PVs). Despite decades of research, detailed spectroscopic studies have seldom been reported, [1,2] primarily because of the considerable challenges to identify chemical transformations that occur on sub-1-mol % of repeat units in the thin films. Yet changes at these levels can be electronically significant. The typical carrier density for LED operation [3] is $1 Â 10 18 cm À3 , which is approximately 0.05 mol % of repeat units, assuming a unit molecular weight of 300 g mol À1 and density of 1.1 g cm À3. For organic FETs, doping at this level can open a parallel source-drain conduction path in the bulk that degrades the shut 'off' and saturation characteristics. [4,5] A simple performance figure-of-merit is the 'on-off' ratio, which for long-channel FETs with a small drain voltage V d and an off-state defined at a gate voltage (V g ) of 0 V is given by i on / i off ¼ mC ox (V g À V th )/(sd), where m is the carrier mobility, C ox is the gate-dielectric capacitance, (V g À V th ) is the effective gate voltage, s is the shunt conductance, and d is the film thickness. For m $ 0.1 cm 2 V À1 s À1 , d $ 30 nm, and typical values for the other parameters, we require s < 10 À8 S cm À1 to give an i on /i off ratio > 10 6

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“…The Er:YAG laser (2.94 µm) is commonly used in medical procedures due to the very high absorption coefficient of water (12000 cm −1 at this wavelength [8]), the main constituent of biological tissue. Consequently this enables precise tissue removal with a small heat penetration depth and high ablation rates.…”

Section: Flexible Delivery For Medical (Er:yag) Lasersmentioning

confidence: 99%

Silica hollow core microstructured fibers for beam delivery in industrial and medical applications

et al. 2015

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The focus of this review is recent work to develop microstructured hollow core fibers for two applications where the flexible delivery of a single mode beam is desired. Also, a brief review of other fiber based solutions is included. High power, short-pulsed lasers are widely used for micro-machining, providing high precision and high quality. However, the lack of truly flexible beam delivery systems limits their application to the processing of relatively small planar components. To address this, hollow-core optical fibers for the 1 µm and green wavelength ranges have been developed. The hollow core overcomes the power delivery limitations of conventional silica fibers arising from non-linear effects and material damage in the solid core. The fibers have been characterized in terms of power handling capability, damage threshold, bend loss and dispersion, and practically demonstrated delivery of high peak power pulses from the nanosecond to the femtosecond regime. Such fibers are ideal candidates for industrial laser machining applications. In laser surgical applications, meanwhile, an Er:YAG laser (2.94 µm) is frequently the laser of choice because the water contained in tissue strongly absorbs this wavelength. If this laser beam is precisely delivered damage to surrounding tissue can be minimized. A common delivery method of surgical lasers, for use in the operating theater, is articulated arms that are bulky, cumbersome and unsuitable for endoscopic procedures. To address this need for flexible mid-IR delivery silica based hollow core fibers have been developed. By minimizing the overlap of the light with glass it is possible to overcome the material absorption limits of silica and achieve low attenuation. Additionally, it is possible to deliver pulse energies suitable for the ablation of both hard and soft tissue even with very small bend radii. The flexibility and small physical size of systems based on these fibers will enable new minimally invasive surgical procedures.

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Lambert Absorption Coefficients of Water in the Infrared*

Cited by 154 publications

References 5 publications

Acid Resistance of Erbium-doped Yttrium Aluminum Garnet Laser–Treated and Phosphoric Acid–Etched Enamels

Acid Resistance of Erbium-doped Yttrium Aluminum Garnet Laser–Treated and Phosphoric Acid–Etched Enamels

Direct Spectroscopic Evidence for a Photodoping Mechanism in Polythiophene and Poly(bithiophene‐alt‐thienothiophene) Organic Semiconductor Thin Films Involving Oxygen and Sorbed Moisture

Silica hollow core microstructured fibers for beam delivery in industrial and medical applications

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