Raman spectroscopy of laser induced material alterations [Elektronische Ressource] / vorgelegt von Michael Bauer

Michael Bauer

Informations

• Publié par: ludwig-maximilians-universitat_munchen
• Publié le: 01 janvier 2010
• Nombre de lectures: 12
• Langue: English
• Poids de l'ouvrage: 4 Mo

Extrait

Raman spectroscopy of laser induced
material alterations
Dissertation
der Fakultat fur Geowissenschaften
der Ludwig-Maximilians-Universitat
Munchen
vorgelegt von
Michael Bauer
Munchen, den 03. Marz 2010 Erstgutachter: Prof. Dr. Robert W. Stark
Zweitgutachter: Prof. Dr. Wolfgang M. Heckl
Disputation: 06. Juli 2010Contents
Table of Contents i
List of Figures iii
List of Abbreviations v
Kurzfassung 1
Abstract 2
1 Introduction 3
2 Raman spectroscopy 5
2.1 Interaction of light with matter . . . . . . . . . . . . . . . . . . . . . 5
2.2 The Raman e ect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.3 Selection rules and Raman line determination . . . . . . . . . . . . . 9
2.4 Inuence of stress and temperature on Raman spectra . . . . . . . . . 10
3 Methods 17
3.1 The confocal Raman microscope set up . . . . . . . . . . . . . . . . . 17
3.1.1 Pinhole inuence and light suppression . . . . . . . . . . . . . 18
3.1.2 Gaussian laser focusing and beam parameters . . . . . . . . . 19
3.2 Local heating due to the focused laser beam . . . . . . . . . . . . . . 21
3.3 Image generation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
4 Spectroscopic characterisation 23
4.1 Silicon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
4.1.1 Phonon dispersion curve and band structure . . . . . . . . . . 23
4.1.2 Raman scattering in silicon . . . . . . . . . . . . . . . . . . . 25
4.1.3 Local heating . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
4.1.4 Experimental results . . . . . . . . . . . . . . . . . . . . . . . 27
4.2 Silicon carbide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
iii Table of Contents
4.2.1 Crystal structure and polytypes . . . . . . . . . . . . . . . . . 28
4.2.2 Phonon structure and mode folding . . . . . . . . . . . . . . . 29
4.2.3 Raman line shift . . . . . . . . . . . . . . . . . . . . . . . . . 31
4.2.4 Local heating . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
4.2.5 Experimental results . . . . . . . . . . . . . . . . . . . . . . . 33
4.3 Alteration of calcium uoride caused by UV-light . . . . . . . . . . . 34
4.3.1 Material properties of calcium uoride . . . . . . . . . . . . . 36
4.3.2 Identication of kerogeneous carbon . . . . . . . . . . . . . . . 37
4.3.3 Experimental results . . . . . . . . . . . . . . . . . . . . . . . 38
4.4 Titanomagnetites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
5 Summary 43
6 References 45
7 Publications 55
7.1 Visualizing stress in silicon microcantilevers using scanning confocal
Raman spectroscopy . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
7.2 Temperature depending Raman line-shift of silicon carbide . . . . . . 61
7.3 Nanoscale residual stress- eld mapping around nanoindents in SiC by
IR s-SNOM and confocal Raman microscopy . . . . . . . . . . . . . . 71
7.4 Exterior surface damage of calcium uoride out coupling mirrors for
DUV lasers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
7.5 Onset of the optical damage in CaF optics caused by deep-UV lasers 952
Appendix I
Acknowledgements XV
Curriculum Vitae XVI
Publication list XVIIList of Figures
2.1 Typical conguration of IR and Raman spectroscopy . . . . . . . . . 6
2.2 Jablonksi energy diagram of the scattering processes . . . . . . . . . . 7
3.1 Schematic of the confocal setup . . . . . . . . . . . . . . . . . . . . . 17
3.2 Lateral resolution of a scattering point as a function of detector size . 18
3.3 Illustrated Gaussian beam of a focused laser beam . . . . . . . . . . . 20
3.4 Filter region for sum ltering and Lorentz