vii
3.3 Discussion................................. 29
4 A Single-pixel CS terahertz imaging system 31
4.1 CS imaging principle........................... 32
4.2 Imaging experiment............................ 33
4.3 Imaging results: Amplitude-only images ................ 35
4.4 Imaging results: Complex images.................... 37
4.5 Discussion................................. 39
5 Terahertz spatial light modulator (SLM) 40
5.1 Metamaterials............................... 41
5.2 First-generation 4 × 4 SLM design................... 42
5.3 Experiments and results......................... 43
5.3.1 Modulation depth......................... 44
5.3.2 Crosstalk ............................. 45
5.3.3 Switching performance...................... 46
5.4 Second-generation 32 × 32 SLM design................. 48
5.5 Characterization experiments and results................ 49
5.6 Discussion................................. 51
6 A future CS terahertz imaging system 56
6.1 Summary of results............................ 56
6.2 Future challenges............................. 58
6.2.1 Terahertz SLM technology.................... 58
6.2.2 Terahertz source power and receiver dynamic range...... 59
6.2.3 Terahertz spectroscopic and phase imaging........... 61
A Implementation of minimization of total variation (min-
63
TV) algorithm