Optical Spectroscopy (eBook)

Methods and Instrumentations

Nikolai V. Tkachenko (Autor)

eBook Download: PDF

2006 | 1. Auflage
322 Seiten
Elsevier Science (Verlag)
978-0-08-046172-4 (ISBN)

Infos

Optical Spectroscopy bridges a gap by providing a background on optics while focusing on spectroscopic methodologies, tools and instrumentations. The book introduces the most widely used steady-state and time-resolved spectroscopic techniques, makes comparisions between them, and provides the methodology for estimating the most important characteristics of the techniques such as sensitivity and time resolution.

Recent developments in lasers, optics and electronics has had a significant impact on modern optical spectroscopic methods and instrumentations. Combining the newest lasers, advanced detectors and other high technology components researchers are able to assemble a spectroscopic instrument with characteristics that were hardly achievable a decade ago. This book will help readers to sourse spectroscopy tools to solve their problems by providing information on the most widely used methods while introducing readers to the principles of quantitative analysis of the application range for each methodology. In addition, background information is provided on optics, optical measurements and laser physics, which is of crucial importance for spectroscopic applications.

* provides an overview of the most popular absorption/emission spectroscopy techniques
* discusses application range, advantages and disadvantages are compared for different spectroscopy methods
* provides introductions to the relevant topics such as optics and laser physics

Inhalt

Cover 1
Contents 10
Preface 6
Contents 10
Introduction 16
Absorption 16
Light absorption in a bulk medium 16
Absorption of complex samples 20
Electronic, vibrational and rotational levels 22
Wavelength, frequency and energy 23
Emission 24
Black body emission 24
Two level system (Einstein's coefficients) 26
Fluorescence and phosphorescence 27
Light amplification 28
Optical spectroscopy 29
Optics and Optical Devices 30
Waves 30
Wave equation 30
Harmonic waves 32
Plane waves 32
Interference 34
Michelson interferometer 35
Fabry-Perot interferometer 37
Interference filters and mirrors 41
Diffraction 42
Fresnel formulation 42
Fraunhofer diffraction (far field approximation) 42
Diffraction grating 44
Monochromator 46
Calculations of optical system (matrix formulation) 48
Geometrical optics approximation 48
Beam transfer matrix 49
Imaging and magnification 50
Lasers for Spectroscopy Applications 54
Laser active medium 54
Laser resonators 56
Resonator with active medium 56
Resonator bandwidth 57
Longitudinal modes 58
Transverse modes 58
Stable and unstable resonators 60
Continuous wave lasers 60
Pulsed lasers 60
Q-Switched lasers 61
Mode-locked lasers 62
Laser amplifiers 63
Main types of lasers 64
Nd:YAG lasers 64
Ion lasers 65
Excimer lasers 65
Dye lasers 66
Ti:sapphire lasers 67
Semiconductor lasers 69
Other lasers used in spectroscopy applications 69
Non-linear optic effect in laser applications 70
Second harmonic 71
Third harmonic 72
Wave mixing 73
Parametric amplification and generation of the light 73
Optical measurements 76
Noise statistics and accuracy of measurements 76
Systematic error and random noise 77
Noise statistics 78
Statistical approach to measurements 84
Noise sources 85
Inaccuracy of indirect measurements 85
Photosensitive devices 87
Photodetector performance parameters 87
Photomultiplier tubes 89
Semiconductor photo-detectors 93
Other photo-detectors 95
Measurements of the light power 95
Measurements of the pulse energy 96
Measurements of the pulse duration 97
Direct methods 97
Autocorrelators (indirect methods) 98
Steady State Absorption Spectroscopy 104
Measurements of the light absorption spectrum 104
Spectrophotometer schemes 106
Single channel scheme 106
Two channel scheme 107
Spectrophotometers with array detectors 110
Main characteristics of spectrophotometers 111
Spectrum range 111
Spectrum resolution 112
Sensitivity and absorption range 113
Instruments, accessories and applications 114
Spectrophotometer specifications 114
Cuvettes for absorption spectroscopy 115
Application notes and examples 117
Steady State Emission Spectroscopy 122
Measurement of the Emission Spectrum 123
Fluorimeter 124
Optical Scheme 124
Use of Array Detectors 126
Evaluation of the Measured Signal 126
Spectrum Correction 128
Quantum yield determination by comparison method 129
Excitation spectrum 130
Sensitivity 132
Wavelength resolution 135
Samples for emission measurements 136
Excitation-monitoring schemes 136
Cuvettes 137
Effect of the sample absorption 137
Fluorimeter specifications 138
Water Raman scattering line as sensitivity test 138
Commercial Fluorimeters 139
Emission of molecular monolayer: An example 140
Flash-photolysis 144
Principles 144
Optical scheme 145
Transient absorbance 146
Differential absorption spectra 148
Excitation schemes 150
Excitation 151
Time resolution and signal-to-noise ratio 153
Pulsed monitoring light 156
Signal averaging 157
Spectrum range and spectrum resolution 158
Measurements of emitting samples 158
Effect of scattering and sample emission 158
Applications in time resolved emission spectroscopy 160
Flash-photolysis instruments 160
Commercial instruments and components 160
Flash-photolysis study of an electron transfer: An example 161
Time correlated single photon counting 166
Principles 166
Excitation sources 168
Detection subsystem 171
Emission detectors 171
Electronics 171
Method characteristics 172
Time resolution 172
Peal-up distortions 172
Sensitivity 173
Signal collection time 175
Spectrum range 176
Comparison with direct emission decay measurements 176
Measurements and data analysis 177
Instrument response function and decay deconvolution 177
Time resolved and decay associated spectra 178
Commercial instruments 180
Measurements of single molecule: Application example 181
Frequency domain emission spectroscopy 186
Theoretical background 186
Measurements scheme 189
Frequency domain instruments 190
Light source 191
Detection system 191
Comparison between frequency and time domain methods 191
Picosecond time resolution with streak camera 194
Operation principles 194
Main characteristics 196
Time resolution 196
Spectrum range 197
Sensitivity 197
Advantages and disadvantages 197
Instrument examples 198
Pump-probe 200
Principles 200
Mono-color scheme 200
Two color scheme 203
Measurements of time resolved spectra 205
Samples and sample excitation schemes 208
Laser systems 209
Detection subsystem and sensitivity 215
Time resolution 216
Group velocity dispersion 217
Effects of sample and optics on time resolution 219
Measurements of the delay spectrum 221
Can it be faster? 222
Sensitivity 225
Application example 225
Photo-induced charge transfer in molecular dyad 225
Pump-probe study of thin films 227
Emission spectroscopy with optical gating methods 232
Frequency up-conversion 232
Principles of up-conversion 232
Time resolution 236
Evaluation of the instrument response time 238
Sensitivity 240
Excitation pulse energy 242
Spectrum range 243
Time resolved spectra 244
Commercial instruments and components 246
Optical Kerr effect 246
Photo-dynamics of semiconductor quantum wells 249
Ultra-fine spectrum resolution 252
Natural line width and broadening 252
Traditional optical tools for high spectrum resolution 254
Lasers for fine spectrum resolution 256
Resonator limited bandwidth 256
Amplification bandwidth and lasing threshold 256
Mode-beating and resonator design for single mode lasers 258
High resolution in absorption spectroscopy 259
Laser spectroscopy 259
Intra-cavity spectroscopy 259
High resolution in emission spectroscopy 260
Spectral hole-burning 263
Polarization measurements 264
Light polarization 264
Interaction of polarized light with media 266
Magic angle 267
Induced anisotropy in fluorescence measurements 268
Anisotropy coefficient 270
Applications of polarized measurements 272
Tools for polarized measurements 272
Optical schemes for polarization measurements 273
Measurements of energy transfer dynamics 274
Analysis of the measurements 278
Indirect measurements 278
Spectral data analysis 279
Kinetics and reaction schemes 282
First order reactions 282
Second order reactions 283
Complex schemes for the first order reactions 284
Time resolved measurements 289
Data fitting 292
Criteria for the fit goodness 292
Minimization of mean square deviation 293
Non-linear least square fit 295
Global fitting of time resolved measurements 298
Qualitative problems 299
Final remarks 302
Photon counting peal-up distortions 304
Relation between Gaussian pulse width and its spectrum 306
Two photon absorption 308
Fit algorithms 310
Stepping algorithm 310
Gradient method 311
Newton method 311
Random search 312
Physical properties of some solvents 314
Bibliography 316
Index 319

Produkt-Details

• Erscheint lt. Verlag: 6.6.2006
• Sprache: englisch
• Themenwelt: Naturwissenschaften ► Chemie ► Analytische Chemie
• Themenwelt: Naturwissenschaften ► Physik / Astronomie ► Angewandte Physik
• Themenwelt: Naturwissenschaften ► Physik / Astronomie ► Optik
• Themenwelt: Technik
• ISBN-10: 0-08-046172-7 / 0080461727
• ISBN-13: 978-0-08-046172-4 / 9780080461724