We report the observation of magneto-optical nonreciprocity in Faraday geometry in a hybrid metamaterial consisting of an Archimedean spiral metasurface and semiconductor InSb that serves as the magneto-optical medium. None of the metamaterial constituents possesses chirality, which is usually a necessary ingredient for optical nonreciprocity in natural materials when the light travels along the magnetic field direction. We also find that our metamaterial can serve as an optical element for polarization control via magnetic field. Another significant property of our hybrid metamaterial is the emergence of the four different transmittance states, which are observed for the four combinations of the positive and negative magnetic field and the direction of the wavevector of light.
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 remarkable
- Award ID(s):
- 1919944
- NSF-PAR ID:
- 10204165
- Publisher / Repository:
- Optical Society of America
- Date Published:
- Journal Name:
- Optics Express
- Volume:
- 28
- Issue:
- 25
- ISSN:
- 1094-4087; OPEXFF
- Format(s):
- Medium: X Size: Article No. 38280
- Size(s):
- Article No. 38280
- Sponsoring Org:
- National Science Foundation
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