Circular spectropolarimetric sensing of life
Patty, C.H.L.
2019
document version
Publisher's PDF, also known as Version of record
Link to publication in VU Research Portal
citation for published version (APA)
Patty, C. H. L. (2019). Circular spectropolarimetric sensing of life.
General rights
Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain
• You may freely distribute the URL identifying the publication in the public portal ?
Take down policy
If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.
E-mail address:
vuresearchportal.ub@vu.nl
1 General Introduction 1 1.1 Introduction . . . 2 1.2 Homochirality . . . 3 1.3 Life detection . . . 3 1.4 Biosignatures . . . 5 1.5 Sensing homochirality . . . 6
1.6 Scope of the dissertation . . . 6
2 Homochirality 9 2.1 Summary . . . 10
2.2 Introduction . . . 10
2.3 Homochirality . . . 11
2.3.1 The homochirality of life . . . 11
2.3.2 The origin of homochirality . . . 12
2.4 Chirality and polarization . . . 15
2.4.1 The discovery of chirality and its relation to the polarization of light . . . 15
2.4.2 Optical rotatory dispersion, electronic circular dichroism and circular polarization . . . 16
2.4.3 Electronic transitions and rotational strength . 20 2.4.4 Exciton coupling . . . 23
2.4.5 Large Aggregates (PSI type) . . . 24
2.5 Remote sensing of homochirality . . . 25
2.5.1 Wavelength considerations . . . 25
2.5.2 In situ observations . . . 27
2.5.3 Solar system observations (remote) . . . 28
2.5.4 Exoplanet observations . . . 29
2.6 Instrumentation . . . 31
2.6.1 Polarization measurement approaches . . . 31
2.6.2 Temporal Modulation . . . 32
2.6.3 Snapshot modulation . . . 34
2.6.4 Mitigating linear polarization cross-talk . . . 36
2.6.5 Current and future instrument concepts . . . . 37
2.7 Conclusion and outlook . . . 40
3 Decaying leaves 43 3.1 Introduction . . . 44
3.2 Materials and Methods . . . 48
3.2.1 Sample collection and storage . . . 48
3.2.2 Circular polarization and circular dichroism . . 49
3.2.3 TreePol . . . 50
3.2.4 Circular dichroism spectropolarimetry . . . 52
3.2.5 Extraction and absorbance/fluorescence spec-troscopy . . . 53
3.3 Results . . . 53
3.3.1 Dark/Daylight differences and weight loss . . . 53
3.3.2 Circular Polarization . . . 53
3.3.3 Transmittance . . . 57
3.3.4 Absorbance and fluorescence of chlorophyll extracts 57 3.3.5 Chlorophyll a concentrations vs V/I over time . 57 3.4 Discussion . . . 59
3.5 Acknowledgments . . . 61
4 Mueller matrix imaging polarimetry 63 4.1 Introduction . . . 64
4.2 Materials and Methods . . . 67
4.2.1 Sample preparation . . . 67
4.2.2 Polarization and Mueller matrix decomposition 67 4.2.3 Mueller matrix polarimeter . . . 71
4.2.4 Data acquisition . . . 72
4.2.5 Spectropolarimetry on maple leaves . . . 73
4.3 Results . . . 74
4.3.1 Mueller matrices . . . 74
4.3.2 Mueller matrix elements m41 and m14 . . . 78
4.3.3 Spatial differences in polarization between veins and normal tissue . . . 78
4.3.4 Mueller matrix decomposition . . . 81 4.4 Discussion . . . 86 4.5 Conclusion . . . 89 4.6 Acknowledgments . . . 89 5 Chloroplast variations 91 5.1 Introduction . . . 92
5.2 Materials and Methods . . . 98
5.2.1 Sample collection . . . 98 5.2.2 Spectropolarimetry . . . 98 5.3 Results . . . 99 5.3.1 Higher Plants . . . 99 5.3.2 Green algae . . . 100 5.3.3 Red algae . . . 101 5.3.4 Brown algae . . . 102 5.3.5 V /I versus absorbance . . . 103 5.4 Discussion . . . 105 5.4.1 Conclusions . . . 109 5.5 Acknowledgments . . . 110 6 Field measurements 111 6.1 Introduction . . . 112
6.2 Materials and methods . . . 115
6.2.1 Polarization . . . 115
6.2.2 Spectropolarimetry . . . 116
6.3 Results . . . 116
6.3.1 Biotic versus abiotic matter . . . 116
6.3.2 Ambient light conditions . . . 118
6.3.3 Laboratory versus in the field measurements . . 118
6.3.4 Laboratory measurements . . . 119 6.4 Discussion . . . 119 6.5 Conclusion . . . 122 7 General discussion 123 7.1 Introduction . . . 124 7.2 Biosignatures . . . 124
7.3 Earth remote sensing . . . 127
7.4 Considerations . . . 128
