Terahertz resonator

An apparatus comprising:

• a tunable terahertz resonator comprising:
• a semiconductor substrate;
• a plurality of metal regions on the semiconductor substrate, a depletion layer being formed in the semiconductor substrate near an interface between each metal region and the semiconductor substrate, each metal region and corresponding depletion layer and corresponding portion of the semiconductor substrate forming a tunable capacitor;
• and
• a plurality of chiral nanostructures each coupled to one of the metal regions, each chiral nanostructure comprising a conducting or semiconducting material and having an inductance, each chiral nanostructure and the corresponding tunable capacitor forming a tunable terahertz resonant circuit;
• and
• a bias circuit to provide a bias voltage across each metal region and the semiconductor substrate to control a capacitance of the tunable capacitor to control a resonant frequency of the resonant circuit;
• wherein at least two of the plurality of tunable terahertz resonant circuits can be controlled independently of each other.

An apparatus comprising:

• a tunable terahertz resonator comprising:
• a tunable capacitor;
• and
• a three-dimensional chiral nanostructure coupled to the tunable capacitor, the nanostructure having an inductance, the nanostructure and the tunable capacitor forming a resonant circuit;
• and
• a bias circuit to apply a bias voltage across the tunable capacitor, the bias voltage controlling a capacitance of the tunable capacitor such that the resonant circuit has a resonant frequency in a range between 0.3 to 30 THz.

A method of operating a terahertz resonator, the method comprising:

• applying a bias voltage across a metal layer and a semiconductor substrate to control a thickness of a depletion region near an interface between the metal layer and the semiconductor substrate, the depletion region having a capacitance that is dependent on the thickness of the depletion region,
• the depletion region being electrically coupled to a chiral nanostructure to form a resonant circuit, the chiral nanostructure being made of a conducting or semiconducting material and having an inductance;
• and
• controlling the bias voltage to adjust a resonant frequency of the resonant circuit.

A method of operating a terahertz resonator, the method comprising:

• applying at least one bias voltage to a plurality of tunable terahertz resonant circuits formed on a semiconductor substrate, each resonant circuit comprising a tunable capacitor electrically coupled to an inductor comprising a chiral nanostructure, the at least one bias voltage being applied to the tunable capacitors to control capacitances of the tunable capacitors,
• the chiral nanostructure having dimensions selected to cause the chiral nanostructure to have a predetermined inductance such that the resonant circuit has a resonant frequency in a range between 0.3 to 30 THz when the bias voltage is within a predetermined range;
• and
• independently controlling the bias voltages applied to at least two of the resonant circuits to independently adjust the resonant frequencies of the at least two resonant circuits.