2017/09/01 by Christopher G. Wade, Matteo Marcuzzi, Wade, Christopher G. +11
Engineering · Physics and Astronomy · #Atomic Physics (physics.atom-ph) #FOS: Physical sciences #Mechanical and Optical Resonators #Spectroscopy and Quantum Chemical Studies #Terahertz technology and applications
paper · pdf · doi:10.48550/arxiv.1709.00262
openalex publication_date 2017/09/01 · openalex created_date 2022/10/01 · openalex updated_date 2026/07/28
There are few demonstrated examples of phase transitions that may be driven directly by terahertz-frequency electric fields, and those that are known require field strengths exceeding 1 MVcm-1. Here we report a room-temperature phase transition driven by a weak (≪ 1 Vcm-1), continuous-wave terahertz electric field. The system consists of caesium vapour under continuous optical excitation to a high-lying Rydberg state, which is resonantly coupled to a nearby level by the terahertz electric field. We use a simple model to understand the underlying physical behaviour, and we demonstrate two protocols to exploit the phase transition as a narrowband terahertz detector: the first with a fast (20 μs) nonlinear response to nano-Watts of incident radiation, and the second with a linearised response and effective noise equivalent power (NEP) ≤ 1 pWHz-1/2. The work opens the door to a new class of terahertz devices controlled with low field intensities and operating around room temperature.