Enhancing Microwave Absorption for Measurement Sensitivity Improvement in Thermoelastic Optical Indicator Microscopy Through Metamaterial Integration
- Abstract
- This study is devoted to improving the measurement sensitivity of thermoelastic optical indicator microscopy (TEOIM) by enhancing microwave absorption within the optical indicator (OI). OI, the fundamental component of TEOIM, consists of a glass substrate coated with a thin film, and the sensitivity of TEOIM is closely related to the efficiency of microwave absorption within the OI. In this work, two approaches were implemented to study microwave absorption enhancement based on the OI. First, the microwave absorption of OI with different film thicknesses was investigated. For this purpose, aluminum-coated glass with film thicknesses of 10nm, 25nm, 50nm, 75 nm, and 100nm was fabricated. Their corresponding microwave absorption was investigated by measuring the microwave near-field. The results show a clear correlation between the thickness of the thin films of OI and the absorption of the microwave near field. 10nm showed an increased absorption of microwaves. This correlation indicates that the reduction of thin film thickness of the OI has a higher sensitivity to the microwave near field. Second, the microwave absorption of OI is investigated by integrating it with the metamaterial absorber. The metamaterial absorber resonating at 11.5 GHz was fabricated on an alumina substrate using silver metal, and the OI was glass coated with ITO thin film. The microwave near-field distribution was measured with and without the metamaterial absorber. Integration of the metamaterial showed improved absorption, and a 10-times increase in sensitivity at the resonance frequency of the metamaterial was calculated. In addition, the improved sensitivity was verified by an experiment comparing the TEOIM measurement system with and without the metamaterial absorber. The results provided compelling evidence of the significant improvement in sensitivity due to the integration of metamaterial absorbers. In addition, using the resonance properties of the metamaterial absorber, the resonance frequency shift with changes in the dielectric environment was investigated. Based on the resonance frequency shift, the equation relating the resonance frequency and the dielectric constant of the tested material was formulated. On this basis, an innovative method for imaging a non-uniform dielectric material was developed.
- Issued Date
- 2024
- Awarded Date
- 2024-02
- Type
- Dissertation
- Alternative Author(s)
- Gitore Shewangzaw Hamelo
- Affiliation
- 제주대학교 대학원
- Department
- 대학원 물리학과
- Advisor
- Lee, Han Ju
- Table Of Contents
- CHAPTER 1 INTRODUCTION 13
1.1 Motivation 14
1.2 Microwave Absorption and Heating Mechanism of Thin Film 15
1.3 Factors Affecting Microwave Heating Efficiency 15
1.4 Optical Indicators . 16
1.5 Statement of the Specific Research Objectives and Aims: 18
CHAPTER 2 AN OVERVIEW OF TEOIM AND METAMATERIALS 22
2.1 Thermoelastic Optical indicator Microscopy (TEOIM) 22
2.2 Components of TEOIM 22
2.3 The existing optical indicators utilized in TEOIM 24
2.4 Measuring principle of TEOIM 24
2.5 Strategies for Enhancing Microwave Signal Absorption in Thin Films and its application for OI 25
2.6 Measuring sensitivity of TEOIM 25
2.7 Metamaterials 27
2.8 Metamaterial Absorbers 29
2.9 General principles of the absorption mechanism metamaterial 31
2.10 Integration of optical indicators (OI) with metamaterial absorbers 33
2.11 Mapping dielectric constant with metamaterial integrated frequency shift 35
2.12 Research gaps in TEOIM and metamaterial absorber integration 37
2.13 Reference 39
CHAPTER 3 MATERIALS METHOD AND MEASURING TECHNIQUE 46
3.1 Instrumentation and Measurement Setup of TEOIM 46
3.1.1 Microwave Signal Generator and Amplification 47
3.2 Optical Polarization and Detection Setup 48
3.3 Metamaterial fabrication 48
3.3.1 Fabrication background 48
3.3.2 Unit cell design 49
3.4 Fabrication of metamaterial absorber 50
3.5 Thin film fabrication 51
3.6 References 53
CHAPTER 4 THIN FILM OPTIMIZATION FOR ENHANCED MICROWAVE ABSORPTION AND MEASUREMENT SENSITIVITY OF TEOIM 55
4.1 Introduction 55
4.2 Experiment 57
4.3 Result and discussion 57
4.4 Conclusion 63
4.5 Reference 64
CHAPTER 5 METAMATERIAL INTEGRATION FOR ENHANCED MICROWAVE ABSORPTION OF THE OPTICAL INDICATOR AND MEASUREMENT SENSITIVITY OF TEOIM 68
5.1 Introduction 68
5.2 Experiment 70
5.3 Design, simulation, and fabrication of metamaterial absorber 70
5.3.1 Experimental setup and working principle 72
5.4 Result and Discussion 73
5.5 Conclusion 83
5.6 Reference 84
CHAPTER 6 NON-DESTRUCTIVE DIELECTRIC MEASUREMENT AND MAPPING USING METAMATERIAL INTEGRATED TEOIM 90
6.1 Introduction 90
6.2 Experiment 92
6.2.1 Design, simulation, and fabrication of metamaterial absorber 92
6.2.2 Validation of decoupled resonators of MM-ABS through CST simulation 93
6.2.3 Experimental setup and working principle 94
6.3 Result and discussion 96
6.3.1 Microwave near-field measurement 96
6.3.2 Equation Formulation 104
6.3.3 Dielectric mapping 105
6.4 Conclusion 110
6.5 Reference 111
CHAPTER 7 CONCLUSIONS 118
- Degree
- Doctor
- Publisher
- 제주대학교 대학원
- Citation
- 기토레 세왕그자오. (2024). Enhancing Microwave Absorption for Measurement Sensitivity Improvement in Thermoelastic Optical Indicator Microscopy Through Metamaterial Integration.
- Appears in Collections:
- Faculty of Applied Energy System > Physics
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