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The Faraday effect due to the cyclotron resonance of conduction electrons in semiconductor InSb allows for nonreciprocity of transmitted light in our Faraday THz isolator operating in the presence of a small magnetic field. We select InSb as an efficient medium for our isolator due to its high electron mobility, low electron effective mass, and narrow band gap. Experimental measurements of the isolator performance indicate a maximum achieved isolation power of 18.8 dB with an insertion loss of −12.6 dB. Our optical analysis of the device points to a remarkablenonreciprocalFabry-Perot effect in the magneto-optical InSb layer as the origin of the multi-fold isolation enhancement. This nonreciprocity occurs as the Fabry-Perot reflections in the forward direction add constructively and enhance the transmittance at certain frequencies, while the Fabry-Perot reflections in the backward direction add destructively and suppress the transmittance at the same frequencies.
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Magnetic field-induced emissivity tuning of InSb-based metamaterials in the terahertz frequency regime
This work demonstrates the magnetic field-induced spectral properties of metamaterials incorporating both indium antimonide (InSb) and tungsten (W) in the terahertz (THz) frequency regime. Nanostructure materials, layer thicknesses and surface grating fill factors are modified, impacting light-matter interactions and consequently modifying thermal emission. We describe and validate a method for determining spectral properties of InSb under an applied direct current (DC) magnetic field, and employ this method to analyze how these properties can be tuned by modulating the field magnitude. Notably, an InSb-W metamaterial exhibiting unity narrowband emission is designed, suitable as an emitter for wavelengths around 55µm (approximately 5.5 THz), which is magnetically tunable in bandwidth and peak wavelength.
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- Award ID(s):
- 1941743
- PAR ID:
- 10290116
- Publisher / Repository:
- Optical Society of America
- Date Published:
- Journal Name:
- Optical Materials Express
- Volume:
- 11
- Issue:
- 9
- ISSN:
- 2159-3930
- Format(s):
- Medium: X Size: Article No. 3141
- Size(s):
- Article No. 3141
- Sponsoring Org:
- National Science Foundation
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