CONTEXT

Until recently, terahertz region of the electromagnetic spectrum has been difficult to reach because of the lack of efficient sources and detectors”. The main issue was waves were absorbed by ambient moisture in the air, killing the signal. Studies for years led to development of photoconductive and electro-optic methods to generate and detect radiation in the THz frequency range. The interest in this the range has been increasing and today much effort is focused on the development of efficient sources, sensitive detectors and suitable modulator in this “THz gap”.

TECHNICAL DESCRIPTION

The invention is about the active components in the terahertz frequency domain, more particularly a modulator for terahertz radiation, and a method to modulate an incident terahertz frequency radiation.
The modulator device can be used in a frequency band between 3 and 30 terahertz and may operate in reflection or in transmission depending of the implementation of the component.

DEVELOPMENT STAGE

• Demonstration of thermal emission modulation through an electrical modulation of the emissivity [Appl. Phys. Lett. 102 081125 (2013)]
• Measurements of THz polarized reflectivity on a doped GaAs grating made of thin walls with subwavelength dimensions and periodicity. Evidence of excitation of a localized surface plasmon-phonon mode along the grating walls. Demonstration of high sensitivity of the reflectivity dip frequency to the surface potential [Appl. Phys. Lett. 100 091103 (2012)]
• Enhenced THz modulation at room temperature : Epsilon-Near-Zero mode [Phys. Rev. Lett. 109 237401 (2012)]
• Experimental demonstration of a THz modulator with a visible optical command [Proc. SPIE 8119, 81190H (2011)]

BENEFITS

This device has the advantages of being able to function at ambient temperature and more effective than existing devices. In fact, the device can be used in a specific range of wavelength where others devices are limited by phonons absorption.

INDUSTRIAL APPLICATIONS

This innovation could be used for civil or military detection (THz transparency measures) to research, safety and astrophysics.

For further information, please contact us (Ref 04139-01)