| Autor: |
Reshma A, Mohandas, Joshua R, Freeman, Michele, Natrella, Mark C, Rosamond, Lalitha, Ponnampalam, Martyn J, Fice, Alwyn J, Seeds, Paul J, Cannard, Michael J, Robertson, David G, Moodie, A Giles, Davies, Edmund H, Linfield, Paul, Dean |
| Rok vydání: |
2017 |
| Zdroj: |
Optics express. 25(9) |
| ISSN: |
1094-4087 |
| Popis: |
We report the generation mechanism associated with nano-grating electrode photomixers fabricated on Fe-doped InGaAsP substrates. Two different emitter designs incorporating nano-gratings coupled to the same broadband antenna were characterized in a continuous-wave terahertz (THz) frequency system employing telecommunications wavelength lasers for generation and coherent detection. The current-voltage characteristics and THz emission bandwidth of the emitters is compared for different bias polarities and optical polarisations. The THz output from the emitters is also mapped as a function of the position of the laser excitation spot for both continuous-wave and pulsed excitation. This mapping, together with full-wave simulations of the structures, confirms the generation mechanism to be due to an enhanced optical electric field at the grating tips resulting in increased optical absorption, coinciding with a concentration of the electrostatic field. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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