Continuous-frequency measurements of high-intensity microwave electric fields with atomic vapor cells

Abstract

We demonstrate continuous-frequency electric field measurements of high-intensity microwaves via optical spectroscopy in a small atomic vapor cell. The spectroscopic response of a room-temperature rubidium atomic vapor in a glass cell is investigated and employed for absolute measurements of K a -band microwave electric fields from ∼200 V/m to >1 kV/m over a continuous frequency range of ±1 GHz (15% band coverage). It is established that in strong microwave fields frequency-specific spectral features allow for electric field measurements over a large continuous frequency range.

Measurement of the Near Field Distribution of a Microwave Horn Using a Resonant Atomic Probe

“…Here, atoms experience the largest microwave field. (ii) Closer inspection of the spectrum at d = 0 in Figure 2d reveals that the peak at 0-detuning (associated with polarization impurities) is small relative to Figure 2b,c, where the horn is at d = +0.24 m and −0.09 m. This demonstrates that the Rydberg atoms experience a microwave field with a relatively pure linear polarization parallel to the polarization of laser beams when the horn is at d = 0, and we clearly observe the two peak EIT-AT spectrum [22]. Meanwhile the AT spectrum at |d| ≈ 0 experiences a strong ac Stark effect, and causes additional splitting of the EIT feature which can be seen on the figure at small d. The Lorentzian nature of the AT split peaks is also degraded by inhomogeneity of the microwave field across the cell.…”

“…The magnitude of the AT splitting, γ AT , is proportional to Ω MW , and so the magnitude of the splitting can be used to make an atom-based microwave field measurement. Rydberg EIT [10][11][12], a quantum coherence effect of the interaction between Rydberg atoms and lasers, will be employed to optically detect the microwave dressed AT splitting γ AT induced by the microwave field [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29]. Additionally, we can use this kind of resonant Rydberg transition and fluorescence to detect THz radiation [30,31].…”

Измерение напряженности электрического поля СВЧ излучения на частоте радиационного перехода между ридберговскими состояниями атомов -=SUP=-85-=/SUP=-Rb

“…Отмечается, что, не внося значительных изменений в конфигурацию экспериментальной установки, можно с ее помощью измерять НЭП в диапазоне частот от нескольких десятков MHz до 500 GHz и выше. К настоящему времени проведены измерения НЭП в диапазоне от 0.8 до 1000 V/m [3]. По сравнению с существующими, базирующимися на антенной технике, методами квантово-оптический метод измерения НЭП обладает более высокой чувствительностью, ограниченной пределом дробовых шумов фотодетектирования 5 µVcm −1 Hz −1 [4], и высокой точностью с 0.5% неопределенностью измерения величины напряженности поля в несколько десятков V/m [5].…”

High-Resolution Antenna Near-Field Imaging and Sub-THz Measurements with a Small Atomic Vapor-Cell Sensing Element

“…Atomic sensors for electric fields are based on quantum-optical spectroscopy of atomic Rydberg states in vapors contained in spectroscopic cells [1]. The approach has been developed as a practical means to exploit the sensitivity of Rydberg atoms [2] to electric fields over a wide frequency range, from the tens of MHz into the sub-THz regime [3]- [7], and has garnered significant interest at NIST and National Metrology Institutes worldwide for the establishment of new atomic standards for electric fields [8]- [10], as well as in industry for the development of quantum electric-field sensing, measurement, and imaging technologies [11], [12]. In the ongoing pursuit of Rydberg-based electric-field sensors and instrumentation for applications, the development and implementation of small atomic vapor-cell sensing elements suitable for high-spatial-resolution detection of mmW and sub-THz electric fields is desired.…”