Confocal Raman Microscopy (eBook)

Preface to the Second Edition 6
Preface to the First Edition 8
Contents 10
Contributors 21
Part I Introduction 25
1 Raman's Discovery in Historical Context 26
1.1 One in About a Million 26
1.2 The Young C.V. Raman and the Discovery of the Effect Named After Him 27
1.3 Observation of the Raman Effect with Sunlight - A Detailed Look at the First Raman Paper, ``A New Type of Secondary Radiation'' 31
1.4 Recognition of Raman's Work by Other Scientists 36
1.5 Raman's Fascination with Crystals and His Time at the Raman Research Institute in Bangalore 38
1.6 Some Important Contributions to Theoretical and Experimental Developments After Raman's Discovery 40
1.7 The First Laser-Raman Spectra 42
1.8 Development of Modern Laser-Raman Spectroscopy and Conclusion 42
1.9 Conclusion 43
References 44
Part II Theory and Technology 45
2 High Resolution Optical and Confocal Microscopy 46
2.1 Introduction 46
2.2 Introduction to Theoretical Considerations in High Resolution Microscopy 48
2.3 Introduction to Confocal Microscopy 48
2.4 Electromagnetic Scattering in Optical Systems 49
2.5 3D-Intensity Distribution in the Focus 50
2.5.1 Large Aperture Angles 51
2.5.2 Transition to Small Aperture Angles 54
2.6 Theory of Image Formation 56
2.6.1 Microscope 56
2.6.2 Confocal Microscope 57
2.6.3 Confocal Raman Microscope 58
2.7 Image Formation for Light Scattering 58
2.7.1 Scattering Point 58
2.7.2 Reflection at a Mirror 59
2.8 Image Formation for Raman Scattering 61
2.8.1 Raman Emitting Point 61
2.8.2 Raman Emission of a Layer 62
2.9 Pinhole Size 63
References 65
3 Introduction to the Fundamentals of Raman Spectroscopy 67
3.1 Introduction 67
3.2 Classical Picture of Light Scattering 68
3.2.1 Frequency-Dependence of Raman Scattering 68
3.2.2 Classical ``Selection Rule'' and Comparison to IR Absorption 70
3.2.3 Scattered Raman Intensity 72
3.2.4 Short Falls of the Classical Picture 73
3.3 Raman Cross-Section Enhancement Mechanisms 73
3.3.1 Resonant Raman Scattering 74
3.3.2 Advantages and Applications of Resonance Raman Scattering 77
3.3.3 Surface Enhanced Raman Scattering 80
References 87
4 Raman Instrumentation for Confocal Raman Microscopy 89
4.1 Introduction 89
4.2 The Development of Raman Microscopes 90
4.3 Confocality 91
4.4 Throughput of a Confocal Raman Microscope 92
4.4.1 Laser Wavelength 92
4.4.2 Excitation Power 94
4.4.3 Objective 94
4.4.4 Microscope Throughput 94
4.4.5 Coupling Between Microscope and Spectrometer 95
4.4.6 Spectrometer Throughput 96
4.4.7 Gratings 96
4.4.8 CCD Detector 96
4.5 Conclusion 106
References 107
5 Software Requirements and Data Analysis in Confocal Raman Microscopy 108
5.1 Introduction 108
5.2 Requirements for Data Acquisition Software 109
5.2.1 Data Acquisition 109
5.2.2 Correlation of Spatial and Spectral Data 112
5.3 Description of the Data Sets Acquired in Confocal Raman Microscopy 112
5.4 Pre-processing of Raman Spectra 113
5.4.1 Cosmic Ray Removal 113
5.4.2 Smoothing 116
5.4.3 Background Subtraction and Subtraction of Reference Spectra 118
5.5 Image Generation 120
5.5.1 Univariate Image Generation 120
5.5.2 Multivariate Image Generation 125
5.6 Image Masks and Selective Average Calculation 131
5.7 Combination of Single Spectra with Multi-spectral Data Sets 132
5.7.1 Basis Spectra 132
5.7.2 Fitting Procedure 132
5.8 Combination of Various Images 133
5.9 The Law of Numbers 135
5.10 Materials and Methods 138
References 139
6 Resolution and Performance of 3D Confocal Raman Imaging Systems 140
6.1 Introduction 140
6.2 Resolution of Confocal Raman Microscopes 141
6.2.1 Resolution - What Is It that We Measure? 141
6.2.2 Spectral Resolution 142
6.2.3 Spatial Resolution 145
6.3 Throughput and Detection Sensitivity 160
6.4 3D Confocal Raman Imaging 163
6.5 Confocal Raman Microscopy on Rough or Inclined Surfaces 165
6.6 Beyond the Diffraction Limit 166
6.6.1 Tip Enhanced Raman Spectroscopy (TERS) 167
6.6.2 Scanning Nearfield Optical Microscopy (SNOM) and Raman 167
6.7 Conclusion 169
References 171
Part III New Materials 173
7 Nano-spectroscopy of Individual Carbon Nanotubes and Isolated Graphene Sheets 174
7.1 Introduction 174
7.2 Individual Carbon Nanotubes 176
7.2.1 Phonons 176
7.2.2 Theory 178
7.2.3 Experiment 179
7.2.4 Microscopy 182
7.2.5 Thermography 182
7.3 Isolated Graphene Sheets 184
7.3.1 Theory 184
7.3.2 Experiment 185
7.3.3 Charge Distributions 189
7.4 Conclusion 191
References 192
8 Characterization of Graphene by Confocal Raman Spectroscopy 194
8.1 Introduction 194
8.2 Electronic Band Structure of Graphene 195
8.3 Phonon Band Structure of Graphene 196
8.4 Raman Spectra of Pristine Graphene 197
8.5 Raman Spectra of Defective Graphene 199
8.6 Raman Spectra of Doped Graphene 200
8.7 Raman Spectra of Strained Graphene 202
8.8 Separating Strain and Doping Signatures in the Raman Spectra of Graphene 204
8.9 Raman Spectroscopy for Monitoring Nanometer-Scale Strain Variations in Graphene 206
8.10 Characterizing the Thickness of Few-Layer Graphene 207
8.11 Summary 209
References 210
9 Low Frequency Raman Scattering of Two-Dimensional Materials Beyond Graphene 212
9.1 Introduction 212
9.2 Phonon Structures of Two Dimensional MX2 214
9.3 Raman Scattering of 2D MX2 215
9.3.1 High-Frequency Raman Scattering of MX2 and Layer Identification 215
9.3.2 Low Frequency Raman Scattering of MX2 and Layer Identification 216
9.4 Application of Raman Spectroscopy in MX2 Layers 218
9.4.1 Strain Analysis of Monolayer MoS2 218
9.4.2 Stacking Behavior of Trilayer MX2 by LF Raman Spectroscopy 219
9.5 Conclusion 222
References 222
Part IV Geosciences 224
10 Raman Spectroscopy and Confocal Raman Imaging in Mineralogy and Petrography 225
10.1 Introduction 225
10.2 Raman Spectroscopy and Imaging as a Mineralogy/Petrography Tool 226
10.2.1 Working with Thin Sections 228
10.2.2 Control of Laser Power 230
10.3 ``Raman Mineralogy'' Using Imaging Raman Techniques 234
10.3.1 Mineral Phase Imaging 234
10.3.2 Crystallographic Orientation Imaging 237
10.3.3 Phase Composition Imaging 239
10.4 Examples of ``Raman Petrography'' Applications 240
10.4.1 Raman Analysis of Shocked Minerals 240
10.4.2 Contextual Imaging of Carbonaceous Materials 241
10.4.3 Fluid Inclusions 245
10.4.4 Ancient Terrestrial Carbonaceous Materials 246
10.5 Raman Mineralogy in Field Geology Studies 248
10.5.1 Extraterrestrial Exploration 248
10.6 Conclusion 249
References 250
11 Application of Raman Imaging in UHPM Research 253
11.1 Introduction 253
11.2 Application of Raman Imaging for Identification of UHPM Relics 254
11.2.1 Metamorphic Diamond 254
11.2.2 Coesite and Quartz 260
11.2.3 K-Bearing Clinopyroxene and Polymorphs of KAlSi3O8 263
11.2.4 Fluid Inclusions 267
11.3 Concluding Remarks 271
References 272
12 Multiscale Chemical Imaging of Complex Biological and Archaeological Materials 275
12.1 Introduction 275
12.2 In-Vivo Raman Imaging 276
12.3 Large-Area Topographic Chemical Imaging 280
12.4 Large-Area Chemical Imaging of Precious Archaeological Samples 282
12.5 Conclusion 284
References 284
Part V Life Sciences and Pharmaceutics 286
13 Raman Micro-spectral Imaging of Cells and Intracellular Drug Delivery Using Nanocarrier Systems 287
13.1 Introduction 288
13.2 Method 291
13.2.1 Data Acquisition 291
13.2.2 Introduction to Data Processing Methods 291
13.2.3 Experimental 295
13.3 Results and Discussion 297
13.3.1 Cell Imaging 297
13.3.2 Intracellular Uptake of Lipids 303
13.3.3 Drug Delivery Systems 307
13.4 Conclusion 316
References 317
14 Raman Imaging of Biomedical Samples 320
14.1 Introduction 320
14.2 Part I 322
14.2.1 Experimental 322
14.2.2 Results and Discussions 325
14.3 Part II 347
14.3.1 Experimental 347
14.3.2 Results and Discussions 349
14.4 Summary and Outlook 357
References 357
15 ISERS Microscopy for Tissue-Based Cancer Diagnostics with SERS Nanotags 360
15.1 Introduction 360
15.2 Brief Tutorial on SERS 362
15.3 SERS Nanoparticle Labels 364
15.3.1 Choice of Metal Colloids as SERS Substrates 365
15.3.2 Labeling with Raman Reporter Molecules 369
15.3.3 Protection and Stabilization 370
15.3.4 Bioconjugation with Antibodies 374
15.3.5 Single-Particle Brightness and Homogeneity of SERS Labels 377
15.4 Application of iSERS Microscopy for Tissue-Based Cancer Diagnostics 379
15.4.1 Localization of Single Proteins by iSERS Microscopy 379
15.4.2 Co-localization of Multiple Proteins by iSERS Microscopy 383
15.4.3 Non-specific Binding 385
15.5 Summary and Outlook 388
References 390
16 Confocal Raman Microscopy in Pharmaceutical Development 393
16.1 Introduction 393
16.1.1 Vibrational Spectroscopy in Pharmaceutical Development 394
16.1.2 Imaging in Pharmaceutical Development 398
16.1.3 Chemical Imaging in Pharmaceutical Development 401
16.1.4 Confocal Raman Microscopy in Pharmaceutical Development 404
16.2 Applications of Confocal Raman Microscopy in Pharmaceutical Development 407
16.2.1 Practical Considerations 407
16.2.2 Investigation of Solid Dosage Forms by Chemical Imaging 414
16.3 Conclusions 426
16.4 Materials and Methods 427
References 427
17 Raman Spectroscopy in Skin Research and Dermal Drug Delivery 432
17.1 The Human Skin - From a Biological Barrier to a Therapeutic Application Site 433
17.1.1 Skin Anatomy and Morphology 433
17.1.2 Drug Delivery to the Human Skin 434
17.2 Analytics in Skin Research and the Potential for Raman Spectroscopy 436
17.2.1 State-of-the-Art Analytics for Skin Research 436
17.2.2 The Potential of Raman Spectroscopy for Skin Analysis 437
17.3 Application of Raman Spectroscopy in Skin Research 439
17.3.1 Analyzing Skin with Raman Spectroscopy 439
17.3.2 Analysis of Human Skin Physiology and Pathological States 444
17.3.3 Skin Penetration and Permeation Studies 448
17.3.4 In Vitro Skin Models 451
17.4 Conclusion and Outlook 455
References 456
18 Characterization of Therapeutic Coatings on Medical Devices 460
18.1 Background 460
18.2 Passive Therapeutic Coatings 462
18.2.1 Coating Thickness 462
18.2.2 Swelling of Hydrophilic Gel Coatings 466
18.3 Active Therapeutic Coatings 467
18.3.1 Coating Morphology 467
18.3.2 Drug Mixed with Single Polymer: Morphology and Elution 468
18.3.3 Drug Mixed with Two Polymers: Blending and Layering 474
18.3.4 Drug Mixed with Two Polymers: Exposure to Water 477
18.3.5 Drug Mixed with Biodegradable Polymer: Drug Elution with Polymer Degradation 478
18.4 Summary 480
References 480
19 Raman Imaging of Plant Cell Walls 482
19.1 Introduction 482
19.2 Plant Cell Walls 483
19.3 Micro-Raman Spectroscopy of Plant Fibers 484
19.4 Plant Cell Wall Imaging by Confocal Raman Microscopy 485
19.4.1 Imaging Cellulose Orientation and Lignin Distribution in Wooden Cell Walls 486
19.4.2 Silica and Cell Wall Composition in Horsetail (Equisetum hyemale) 489
19.5 Outlook 491
19.6 Materials and Methods 492
References 492
Part VI Materials Science 494
20 Confocal Raman Imaging of Polymeric Materials 495
20.1 Introduction 495
20.2 Raman Imaging of Isotactic Polypropylene (IPP) 497
20.3 Raman Imaging of Polymer Blends 502
20.3.1 Raman Imaging of Thin Films of the Polymer Blend: Polystyrene (PS) - Ethyl-Hexyl-Acrylate (EHA) 503
20.3.2 Raman Imaging of Thin Films of the Polymer Blend Ethyl-Hexyl-Acrylate (EHA) - Styrene-Butadiene Rubber (SBR) 506
20.3.3 Raman Imaging of Thin Films of the Polymer Blend PS-EHA-SBR 508
20.4 Polymer Coatings 508
20.4.1 Acrylic Paints 510
20.4.2 Adhesives 511
20.5 Additives in Polymer Matrices 512
20.6 Summary 515
References 516
21 Stress Analysis by Means of Raman Microscopy 518
21.1 Introduction 518
21.1.1 Theoretical Background 519
21.1.2 Measuring in Conventional Backscattering Configuration 521
21.1.3 Off-Axis Raman Spectroscopy 523
21.1.4 Stress Tensor Analysis in Backscattering Raman Microscopy 524
21.2 Case Studies 527
21.2.1 3-D Raman Spectroscopy Measurements 527
21.2.2 ZnO 530
21.2.3 The Influence of Stress on the Peak Position of Polymers 533
21.3 Discussion 535
References 537
22 Confocal Raman Microscopy Can Make a Large Difference: Resolving and Manipulating Ferroelectric Domains for Piezoelectric Engineering 539
22.1 Raman Spectroscopy and Confocal Raman Imaging: A Very Useful Technique for the Quick Evaluation of the Structure and the Properties of Lead-Free Piezoceramics 540
22.1.1 A Classical Approach of Raman Spectroscopy for In Situ Monitoring of Structural Changes 540
22.1.2 Raman Imaging: Can It Make a Significant Difference? 544
22.2 The Study of (K,Na)NbO3-Based Lead-Free Piezoelectric Ceramics: Identification of the Secondary Phase Location Using Confocal Raman Imaging 546
22.3 High Spatial Resolution Structure of (K,Na)NbO3 Lead–Free Ferroelectric Domains 548
22.3.1 Simultaneous Determination of Topographic and Structural Features by CRM Coupled with AFM 550
22.3.2 Insights into the Details of the Ferroelectric Domain Structure 552
22.3.3 Some Clues About the Origin of the Ferroelectric Domain Structure: The Stress Sensitivity of Raman Spectroscopy 553
22.4 A Potential Technological Application: Ferroelectric Domain Wall Motion Induced by Polarized Light 555
22.4.1 Resolving the Origin of the BaTiO3 Complex Domain Structure 556
22.4.2 ``In Situ'' Ferroelectric Domain Switching Using a Polarized Light Source: A Potential Technological Application 559
22.5 Outlook 562
References 563
Part VII Correlative Microscopy 565
23 RISE: Correlative Confocal Raman and Scanning Electron Microscopy 566
23.1 Introduction 567
23.2 Combining Scanning Electron Microscopy and Confocal Raman Spectroscopy 568
23.2.1 SEM and SEM-Based Microanalysis 568
23.3 Confocal Raman Imaging 570
23.4 Combining SEM/EDS and Confocal Raman Spectroscopy 570
23.4.1 Correlation of SEM and Raman Information 570
23.4.2 Toward an Integrated Solution 571
23.4.3 Confocal Raman in the SEM 572
23.5 Correlative Confocal Raman/SEM Imaging 573
23.5.1 Confocal Raman Microscopy in an SEM 573
23.5.2 Choice of SEM for Integration with a Confocal Raman Microscope 573
23.6 Application Examples of CRM Coupled to SEM 575
23.6.1 Raman-SEM (RISE) Analysis of Graphene 575
23.6.2 RISE Microscopy of MoS2 576
23.6.3 Geoscience Application Example: Mineral Characterization of an Asbestos Fiber Bundle 577
23.6.4 Geoscience Application Example: Drill Core Sample 582
23.6.5 RISE Analysis of Polymorphs: Correlating Structure with Chemical Phases 584
23.7 Conclusion 585
References 586
Index 588