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Bergström, David
Publications (10 of 11) Show all publications
Bergström, D. (2008). The absorptance of metal surfaces to Nd:YAG/Nd:YLF laser light. In: 3rd Pacific International Conference on Applications of Lasers and Optics, PICALO 2008 - Conference Proceedings: . Paper presented at 3rd Pacific International Conference on Applications of Lasers and Optics, PICALO 2008; Beijing; China; 16 April 2008 through 18 April 2008; Code 80519 (pp. 375-380).
Open this publication in new window or tab >>The absorptance of metal surfaces to Nd:YAG/Nd:YLF laser light
2008 (English)In: 3rd Pacific International Conference on Applications of Lasers and Optics, PICALO 2008 - Conference Proceedings, 2008, p. 375-380Conference paper, Published paper (Refereed)
Abstract [en]

The absorptance of the metal surfaces used in Laser Material Processing depends strongly upon the particular surface conditions, including the degree of roughness and oxidation. In this paper the influence of surface topography on Nd:YAG/Nd:YLF laser absorptance has been studied using 3D ray-tracing simulations. The results have increased the understanding of how surface roughness influences the laser-workpiece coupling efficiency.

Keywords
Absorptance; Coupling efficiency; Laser material processing; Metal surfaces; Ray tracing simulation; Surface conditions; Work pieces; YLF laser
National Category
Engineering and Technology
Identifiers
urn:nbn:se:miun:diva-28878 (URN)2-s2.0-77953191641 (Scopus ID)978-091203589-5 (ISBN)
Conference
3rd Pacific International Conference on Applications of Lasers and Optics, PICALO 2008; Beijing; China; 16 April 2008 through 18 April 2008; Code 80519
Available from: 2016-09-22 Created: 2016-09-22 Last updated: 2016-09-22Bibliographically approved
Bergström, D. (2008). The Absorption of Laser Light by Rough Metal Surfaces. (Doctoral dissertation).
Open this publication in new window or tab >>The Absorption of Laser Light by Rough Metal Surfaces
2008 (English)Doctoral thesis, comprehensive summary (Other academic)
Series
Doctoral thesis / Luleå University of Technology, ISSN 1402-1544 ; 2008:08
Keywords
absorptance, reflectance, laser, metals, roughness, integrating sphere
National Category
Materials Engineering
Identifiers
urn:nbn:se:miun:diva-6878 (URN)6064 (Local ID)6064 (Archive number)6064 (OAI)
Public defence
(English)
Available from: 2008-11-03 Created: 2008-11-03 Last updated: 2009-03-10Bibliographically approved
Bergström, D., Kaplan, A. & Powell, J. (2008). The absorption of light by rough metal surfaces - a three-dimensional ray-tracing analysis. Journal of Applied Physics, 103(10), 103515-
Open this publication in new window or tab >>The absorption of light by rough metal surfaces - a three-dimensional ray-tracing analysis
2008 (English)In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 103, no 10, p. 103515-Article in journal (Refereed) Published
Abstract [en]

The laser absorptance of rough surfaces has been investigated by using Monte Carlo simulations based on three-dimensional (3D) ray tracing. The influence of multiple scattering, shadowing, and the Fresnel-equation based angle dependence is discussed. The 3D results are compared to previously published results from a two-dimensional ray-tracing analysis and the different applications of the two models are explained.

Keywords
absorptance, light, surface roughness, angle of incidence, laser
National Category
Materials Engineering
Identifiers
urn:nbn:se:miun:diva-6877 (URN)10.1063/1.2930808 (DOI)000256303800036 ()2-s2.0-44649200482 (Scopus ID)6063 (Local ID)6063 (Archive number)6063 (OAI)
Available from: 2008-11-13 Created: 2008-11-03 Last updated: 2017-12-14Bibliographically approved
Bergström, D., Powell, J. & Kaplan, A. F. (2007). A ray-tracing analysis of the absorption of light by smooth and rough metal surfaces. Journal of Applied Physics, 101(11), Article ID 113504.
Open this publication in new window or tab >>A ray-tracing analysis of the absorption of light by smooth and rough metal surfaces
2007 (English)In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 101, no 11, article id 113504Article in journal (Refereed) Published
Abstract [en]

Ray tracing has been employed to investigate the absorption of light by smooth and random rough metal surfaces. For normally incident light the absorptance of the surface increases with surface roughness. However, for light incident at a tangent to the surface the absorptance-surface roughness relationship is more complex. For example, in certain cases the absorptance can rise, fall, and rise again as the surface roughness increases. In this paper this complex absorptance-roughness relationship is defined and explained. The wavelengths of the light chosen for this study correspond to the primary and secondary output wavelengths of Nd:YAG lasers.

National Category
Materials Engineering
Identifiers
urn:nbn:se:miun:diva-8462 (URN)10.1063/1.2738417 (DOI)000247306000031 ()2-s2.0-34250671633 (Scopus ID)
Available from: 2009-01-26 Created: 2009-01-26 Last updated: 2017-12-14Bibliographically approved
Bergström, D., Powell, J. & Kaplan, A. (2007). Absorptance of Non-Ferrous Alloys to Nd:YLF and Nd:YAG Laser Light at Room Temperature. Applied Optics, 46(8), 1290-1301
Open this publication in new window or tab >>Absorptance of Non-Ferrous Alloys to Nd:YLF and Nd:YAG Laser Light at Room Temperature
2007 (English)In: Applied Optics, ISSN 1559-128X, E-ISSN 2155-3165, Vol. 46, no 8, p. 1290-1301Article in journal (Refereed) Published
Abstract [en]

The measurement of absorptance is important for the analysis and modelling of laser-material interactions. Unfortunately, most of the absorptance data presently available considers only polished pure metals rather than the commercially available (unpolished, oxidised) alloys which are actually being processed in manufacturing. This paper presents the results of absorptance measurements carried out at room temperature on as-received engineering grade non-ferrous metals (Al, Cu and Zn alloys). The measurements were made using an integrating sphere with an Nd:YLF laser at two wavelengths (1053nm and 527nm � which means that the results are also valid for Nd:YAG radiation at 1064nm and 532nm). The absorptance results obtained differ considerably from existing data for polished, pure metals and should help improve the accuracy of laser-material interaction models. Some clear trends were identified. For all 22 cases studied the absorptance was higher than for ideal pure, polished metals. For all Al- and Cu-samples the absorptance was higher for the green than it was for the infrared wavelength, while for all Zn-coatings this trend was reversed. No clear correlation between absorptance and surface roughness was found at low roughness values (Sa 0.15 � 0.60) but one, rougher set of samples (Sa 2.34), indicated a roughness-absorptance correlation at higher roughness levels.

Keywords
Laser materials processing; Integrating spheres; Roughness; Surface measurements, roughness.
National Category
Materials Engineering
Identifiers
urn:nbn:se:miun:diva-4120 (URN)10.1364/AO.46.001290 (DOI)000244637200015 ()2-s2.0-34047132890 (Scopus ID)4763 (Local ID)4763 (Archive number)4763 (OAI)
Note

VR-Materials Science

Available from: 2008-09-30 Created: 2009-11-02 Last updated: 2017-10-31Bibliographically approved
Bergström, D., Kaplan, A. & Powell, J. (2007). Light scattering and absorption in Gaussian random rough metal surfaces using the geometric optics approximation. In: 20th Meeting on Mathematical Modelling of Material Processing with Lasers: .
Open this publication in new window or tab >>Light scattering and absorption in Gaussian random rough metal surfaces using the geometric optics approximation
2007 (English)In: 20th Meeting on Mathematical Modelling of Material Processing with Lasers, 2007Conference paper, Published paper (Refereed)
Keywords
absorptance, light, laser, surface roughness, metals, ray-tracing
National Category
Materials Engineering
Research subject
Identifiers
urn:nbn:se:miun:diva-6881 (URN)6068 (Local ID)6068 (Archive number)6068 (OAI)
Available from: 2008-12-02 Created: 2008-11-03 Last updated: 2008-12-02Bibliographically approved
Bergström, D., Powell, J. & Kaplan, A. (2007). Nd:YAG laser absorptance by rough metal surfaces. In: 26th International Congress on Applications of Lasers and Electro-Optics, ICALEO 2007 - Congress Proceedings: . Paper presented at 26th International Congress on Applications of Lasers and Electro-Optics, ICALEO 2007; Orlando, FL; United States; 29 October 2007 through 1 November 2007; Code 80802.
Open this publication in new window or tab >>Nd:YAG laser absorptance by rough metal surfaces
2007 (English)In: 26th International Congress on Applications of Lasers and Electro-Optics, ICALEO 2007 - Congress Proceedings, 2007Conference paper, Published paper (Refereed)
Abstract [en]

The Nd:YLF/Nd:YAG laser absorptance of rough metal surfaces has been investigated using 3D ray tracing simulations on computer-generated Gaussian random rough metal surfaces. The impact of multiple scattering, shadowing and Fresnel-equation based angle dependence on the overall absorption is discussed.

Keywords
Absorptance; Angle dependence; Equation based; Fresnel; Gaussians; Metal surfaces; ND : YAG lasers; Ray tracing simulation; YAG laser
National Category
Engineering and Technology
Identifiers
urn:nbn:se:miun:diva-28879 (URN)2-s2.0-77954196579 (Scopus ID)978-091203588-8 (ISBN)
Conference
26th International Congress on Applications of Lasers and Electro-Optics, ICALEO 2007; Orlando, FL; United States; 29 October 2007 through 1 November 2007; Code 80802
Available from: 2016-09-22 Created: 2016-09-22 Last updated: 2016-09-22Bibliographically approved
Bergström, D., Powell, J. & Kaplan, A. (2007). The absorptance of steels to Nd:YLF and Nd:YAG laser light at room temperature. Applied Surface Science, 253(11), 5017-5028
Open this publication in new window or tab >>The absorptance of steels to Nd:YLF and Nd:YAG laser light at room temperature
2007 (English)In: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 253, no 11, p. 5017-5028Article in journal (Refereed) Published
Abstract [en]

The measurement of absorptance is important for the analysis and modelling of laser-material interactions. Unfortunately, most of the absorptance data presently available considers only polished pure metals rather than the commercially available (unpolished, oxidised) alloys, which are actually being processed in manufacturing. This paper presents the results of absorptance measurements carried out at room temperature on as-received engineering grade steels including hot and cold rolled mild steel and stainless steels of various types. The measurements were made using an integrating sphere with an Nd:YLF laser at two wavelengths (1053 and 527 nm, which means that the results are also valid for Nd:YAG radiation at 1064 and 532 nm). The absorptance results obtained differ considerably from existing data for polished, pure metals and should help improve the accuracy of laser-material interaction models. Some clear trends were identified; for all materials studied, the absorptance was considerably higher than the previously published values for the relevant pure metals with polished surfaces. For all 15 samples the absorptance was higher for the green than for the infrared wavelength. No clear trend correlating the absorptance with the roughness was found for mild steel in the roughness range Sa 0.4-5.6 μm. A correlation between absorptance and roughness was noted for stainless steel for Sa values above 1.5 μm.

Keywords
Laser material processing, Absorptance, Steels, Integrating sphere
National Category
Materials Engineering
Identifiers
urn:nbn:se:miun:diva-4121 (URN)10.1016/j.apsusc.2006.11.018 (DOI)000245500200032 ()2-s2.0-33847246442 (Scopus ID)4764 (Local ID)4764 (Archive number)4764 (OAI)
Note

VR-Materials Science

Available from: 2008-09-30 Created: 2009-11-02 Last updated: 2017-10-31Bibliographically approved
Bergström, D. (2006). The reflectance of steels and non-ferrous alloys: 2nd Pacific International Conference on Application of Lasers and Optics 2006. In: PICALO 2006 - 2nd Pacific International Conference on Applications of Laser and Optics - Conference Proceedings: . Paper presented at PICALO 2006 - 2nd Pacific International Conference on Applications of Laser and Optics; Melbourne, VIC; Australia; 3 April 2006 through 5 April 2006; Code 74106 (pp. 140-145).
Open this publication in new window or tab >>The reflectance of steels and non-ferrous alloys: 2nd Pacific International Conference on Application of Lasers and Optics 2006
2006 (English)In: PICALO 2006 - 2nd Pacific International Conference on Applications of Laser and Optics - Conference Proceedings, 2006, p. 140-145Conference paper, Published paper (Other academic)
Abstract [en]

The measurement of reflectance is important for the analysis and modelling of laser-material interactions. Unfortunately, most of the reflectance data presently available consider only polished pure metals rather than the commercially available (unpolished, oxidised) alloys which are actually being processed. This paper presents the results of reflectance measurements carried out on as-received engineering grade metals including: hot and cold rolled mild steel, zinc coated mild steel, stainless steel, aluminium alloys, copper and brass. The measurements were made using an integrating sphere with an Nd:YLF laser at two wavelengths (1053 nm and 527 nm). The results obtained differ considerably from existing data for polished, pure metals and should help to improve the accuracy of laser-material interaction models.

Keywords
laser material processing, absorptance, reflectance, integrating sphere
National Category
Natural Sciences Production Engineering, Human Work Science and Ergonomics Materials Engineering Other Engineering and Technologies
Identifiers
urn:nbn:se:miun:diva-1334 (URN)2-s2.0-56349129704 (Scopus ID)4760 (Local ID)0912035846 (ISBN)978-091203584-0 (ISBN)4760 (Archive number)4760 (OAI)
Conference
PICALO 2006 - 2nd Pacific International Conference on Applications of Laser and Optics; Melbourne, VIC; Australia; 3 April 2006 through 5 April 2006; Code 74106
Available from: 2008-09-30 Created: 2008-09-30 Last updated: 2016-09-23Bibliographically approved
Bergström, D., Kaplan, A. & Powell, J. (2005). Laser absorption measurements in opaque solids. In: 10th NOLAMP Conference : the 10th Nordic Laser Materials Processing Conference, 17-19 August 2005, Luleå Sweden: (pp. 444-). Luleå: Luleå University of Technology
Open this publication in new window or tab >>Laser absorption measurements in opaque solids
2005 (English)In: 10th NOLAMP Conference : the 10th Nordic Laser Materials Processing Conference, 17-19 August 2005, Luleå Sweden, Luleå: Luleå University of Technology , 2005, p. 444-Conference paper, Published paper (Refereed)
Abstract [en]

In LaserMaterial Processing, an understanding of the fundamental absorption mechanisms plays a vital role in determining the optimum processing parameters and conditions. The absorptance, which characterizes how much a material absorbs, can alter during a processing application, as a result of melting, boiling, structural changes of the surface, oxidation, plasma formation, etc. To gain knowledge of these complex processes, a combination of experimental as well as of theoretical work is required. In this paper, an overview of the most common experimental methods and techniques to measure laser absorption in opaque solids, such as metals, will be presented.

Place, publisher, year, edition, pages
Luleå: Luleå University of Technology, 2005
Keywords
absorptance, reflectance, emittance, calorimetry, integrating sphere, integrating mirror
National Category
Materials Engineering Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:miun:diva-3306 (URN)3240 (Local ID)91-631-7228-3 (ISBN)3240 (Archive number)3240 (OAI)
Available from: 2008-09-30 Created: 2009-03-06Bibliographically approved
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