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A terahertz-driven non-equilibrium phase transition in a room temperature atomic vapour
C G Wade1,2, M Marcuzzi3,4, E Levi3,4
1Joint Quantum Centre (JQC) Durham-Newcastle, Department of Physics, Durham University, Durham, DH1 3LE, UK. christopher.wade@physics.ox.ac.uk.
Nature Communications
|September 5, 2018
Summary
Researchers achieved a phase transition using weak terahertz electric fields, enabling a new type of sensitive terahertz detector. This breakthrough operates at room temperature with low power requirements.
Area of Science:
- Quantum Optics
- Condensed Matter Physics
- Terahertz Science and Technology
Background:
- Phase transitions typically require high terahertz electric fields (>1 MV/cm).
- Existing terahertz detectors often lack sensitivity or require cryogenic temperatures.
Purpose of the Study:
- To demonstrate a non-equilibrium phase transition driven by low-intensity terahertz electric fields.
- To develop novel terahertz detectors based on this phase transition.
Main Methods:
- Utilized room temperature caesium vapor excited to Rydberg states.
- Resonantly coupled Rydberg states using a continuous-wave terahertz electric field.
- Employed a simple model to analyze the physical behavior.
Main Results:
- Achieved a non-equilibrium phase transition with terahertz electric fields significantly below 1 V/cm.
- Demonstrated two protocols for narrowband terahertz detection.
- Achieved fast (20 μs) non-linear response to nano-Watt radiation and linear response with noise equivalent power ≤1 pW/Hz-1/2.
Conclusions:
- Established a new method for inducing phase transitions with low terahertz field strengths.
- Paved the way for room-temperature terahertz devices operable at low field intensities.
- Showcased the potential of Rydberg-state systems for sensitive terahertz detection.
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