Measuring the absolute absorptance of optical laser components

Willamowski, Uwe; Ristau, Detlev; Welsch, E.

doi:10.1364/ao.37.008362

Cited by 84 publications

(35 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…For the three samples, the fitted H values are 6.13 K · m −1 (BK7), 4.85 K · m −1 (fused silica), and 0.109 K · m −1 (Ge). From the thermal loss coefficient H , a thermal convective coefficient h [13] that is related only to the environment of the sample can be calculated. Namely H = h/K th , where K th is the thermal conductivity of the sample.…”

Section: Resultsmentioning

confidence: 99%

“…The temperature within the sample increases due to the absorption of the incident laser energy. A set of high-sensitivity negative temperature coefficient (NTC) temperature sensors attached to the rear surface of the sample measure the absorption-induced temperature rise at positions which are 7 mm away from the laser irradiation site (which is approximately the center of the sample) [13]. The absorptance is then determined by fitting the temporal behavior of the temperature rise within the sample to either the simplified or the accurate temperature model.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Simultaneous Absorptance and Thermal-Diffusivity Determination of Optical Components with Laser Calorimetry Technique

Wang

2012

Int J Thermophys

View full text Add to dashboard Cite

The laser calorimetry (LCA) technique is used to determine simultaneously the absorptances and thermal diffusivities of optical components. An accurate temperature model, in which both the finite thermal conductivity and the finite sample size are taken into account, is employed to fit the experimental temperature data measured with an LCA apparatus for a precise determination of the absorptance and thermal diffusivity via a multiparameter fitting procedure. The uniqueness issue of the multiparameter fitting is discussed in detail. Experimentally, highly reflective (HR) samples prepared with electron-beam evaporation on different substrates (BK7, fused silica, and Ge) are measured with LCA. For the HR-coated sample on a fused silica substrate, the absorptance is determined to be 15.4 ppm, which is close to the value of 17.6 ppm, determined with a simplified temperature model recommended in the international standard ISO11551. The thermal diffusivity is simultaneously determined via multiparameter fitting to be approximately 6.63 × 10 −7 m 2 · s −1 with a corresponding square variance of 4.8 × 10 −4 . The fitted thermal diffusivity is in reasonably good agreement with the literature value (7.5 × 10 −7 m 2 · s −1 ). Good agreement is also obtained for samples with BK7 and Ge substrates.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Simultaneous Absorptance and Thermal-Diffusivity Determination of Optical Components with Laser Calorimetry Technique

Wang

2012

Int J Thermophys

View full text Add to dashboard Cite

show abstract

“…This technique can detect absorptance of the order of a few parts per million. 2 One means to separate surface and bulk absorptance is to study samples with different thicknesses. If the surfaces are identical, then a plot of measured absorptance versus sample thickness extrapolated to zero thickness reveals the surface absorptance.…”

Section: Introductionmentioning

confidence: 99%

Optical absorption, depolarization, and scatter of epitaxial single-crystal chemical-vapor-deposited diamond at 1.064μm

et al. 2007

View full text Add to dashboard Cite

Epitaxial single-crystal chemical-vapor-deposited diamond with ͑100͒ crystal orientation is obtained from Element Six ͑Ascot, United Kingdom͒ and Apollo Diamond ͑Boston, Massachusetts͒. Both companies supply 5 ϫ 5-mm squares with thicknesses of 0.35 to 1.74 mm. Element Six also provides disks with a state of the art diameter of 10 to 11 mm and a thickness of 1.0 mm. The absorption coefficient measured by laser calorimetry at 1.064 m is 0.003 cm −1 for squares from Element Six and 0.07 cm −1 for squares from Apollo. One Apollo specimen has an absorption coefficient near those of the Element Six material. Absorption coefficients of Element Six disks are 0.008 to 0.03 cm −1 . Each square specimen can be rotated between orientations that produce minimum or maximum loss of polarization of a 1.064-m laser beam transmitted through the diamond. Minimum loss is in the range 0 to 11% ͑mean =5%͒ and maximum loss is 8 to 27% ͑mean= 17% ͒. Element Six disks produce a loss of polarization in the range 0 to 4%, depending on the angle of rotation of the disk. Part of the 0.04 to 0.6% total integrated optical scatter in the forward hemisphere at 1.064 m can be attributed to surface roughness.

show abstract

“…Thus, there is a need for sensitive characterization technique, which can additionally probe the homogeneity of the sample to measure the optical absorption in specified sample regions, such as regions with incorporated inclusions or other defects. Classical transmission measurements are not sensitive enough and laser calorimetry [3] is mainly used to evaluate the optical absorption at the CO 2 laser wavelength. The faster method for low absorption measurements in highly transparent materials is the photothermal deflection technique (PTD) working in a collinear mode [4].…”

Section: Introductionmentioning

confidence: 99%

Local Variations and Temperature Dependence of Optical Absorption Coefficient in Natural IIa Type and CVD Diamond Optical Windows

Remeš¹,

Nesládek²,

Pickles

2001

phys. stat. sol. (a)

View full text Add to dashboard Cite

We used the photothermal deflection (PTD) technique working in a collinear mode to measure optical absorption coefficient at the CO 2 laser wavelength (10.6 mm) of polished CVD and natural type IIa diamond optical windows. The CO 2 pump beam is focused to a spot size of about 100 mm, enabling the localized detection of variations in the optical absorption coefficient. For the first time, we present detailed 2D absorption maps of CVD diamond optical windows. The regions of enhanced absorption are visualized. The enhanced absorption above 0.03 cm --1 at 300 K is caused by non-diamond inclusions ("black spots"). The residual absorption coefficient 0.03 cm --1 at 300 K increases almost one decade at 900 K in natural type IIa single crystal diamond. Our results indicate that the intrinsic optical absorption at 10.6 mm is caused by two-phonon acoustic-acoustic interactions.

show abstract

Measuring the absolute absorptance of optical laser components

Cited by 84 publications

References 15 publications

Simultaneous Absorptance and Thermal-Diffusivity Determination of Optical Components with Laser Calorimetry Technique

Simultaneous Absorptance and Thermal-Diffusivity Determination of Optical Components with Laser Calorimetry Technique

Optical absorption, depolarization, and scatter of epitaxial single-crystal chemical-vapor-deposited diamond at 1.064μm

Local Variations and Temperature Dependence of Optical Absorption Coefficient in Natural IIa Type and CVD Diamond Optical Windows

Contact Info

Product

Resources

About