The phase noise of incident light fields can be converted into amplitude noise via absorption and dispersion effects in media under electromagnetically induced transparency. The conversion process is sensitive to two-photon detuning. This effect can be used to perform a novel type of Rydberg spectroscopy. We present experimental measurements of the phase noise spectrum (PNS) with Rydberg atoms in a cesium vapor cell. Furthermore, to explore microwave field measurements, a modulation-enhanced PNS approach is proposed.The phase noise of incident light fields can be converted into amplitude noise via absorption and dispersion effects in media under electromagnetically induced transparency. The conversion process is sensitive to two-photon detuning. This effect can be used to perform a novel type of Rydberg spectroscopy. We present experimental measurements of the phase noise spectrum (PNS) with Rydberg atoms in a cesium vapor cell. Furthermore, to explore microwave field measurements, a modulation-enhanced PNS approach is proposed.

arXiv:2111.10019Nov 19, 20210 citations

Microwave electric field measurement using frequency modulation spectroscopy in Rydberg atoms vapor cells

Santosh Kumar, Haoquan Fan, Akbar Jahangiri Jozani +2 more

We recently proposed a method to detect weak microwave electric field ~8µV/cm with sensitivity ~ 30 µV cm−1Hz−1/2 [Nat. Phys. 8, 819 (2012)]. This technique is based on Rydberg atoms using the concept of electromagnetically induced transparency in room temperature vapor cells. Here we show that frequency modulation spectroscopy with active control of residual amplitude modulation improves the read out signal-to-noise. The method has the potential for high sensitivity and can be self-calibrated.We recently proposed a method to detect weak microwave electric field ~8µV/cm with sensitivity ~ 30 µV cm−1Hz−1/2 [Nat. Phys. 8, 819 (2012)]. This technique is based on Rydberg atoms using the concept of electromagnetically induced transparency in room temperature vapor cells. Here we show that frequency modulation spectroscopy with active control of residual amplitude modulation improves the read out signal-to-noise. The method has the potential for high sensitivity and can be self-calibrated.

International conference on fiber optics and photonicsJan 1, 20160 citations

Sub-shot-noise Rydberg EIT spectrum

Hongmei Yan, Mingyong Jing, Yanjie Tong +8 more

Abstract Atom-based sensing with optical readout is fundamentally limited by photon shot noise. Squeezed light can effectively suppress this noise of optical readout, thereby enabling measurement sensitivities beyond the standard quantum limit, but their application in light–atom hybrid systems is often hindered by absorption losses of atomic medium. Here, we demonstrate the first realization of electromagnetically induced transparency spectrum in a Rydberg-atom system using a squeezed probe field that surpasses the photon shot noise limit. Our theoretical model identifies atomic transit and absorption-induced losses as the primary factors limiting squeezing preservation. Experimentally, we engineer the atomic ensemble as a medium with tunable transmittance by employing Doppler-matched velocity-selective excitation to suppress absorption, achieving a squeezing transmission of 90.4 $\%$ % for -1.7 dB squeezed light through a cesium vapor cell. This work is a critical step towards quantum-enhanced Rydberg atom sensors.Abstract Atom-based sensing with optical readout is fundamentally limited by photon shot noise. Squeezed light can effectively suppress this noise of optical readout, thereby enabling measurement sensitivities beyond the standard quantum limit, but their application in light–atom hybrid systems is often hindered by absorption losses of atomic medium. Here, we demonstrate the first realization of electromagnetically induced transparency spectrum in a Rydberg-atom system using a squeezed probe field that surpasses the photon shot noise limit. Our theoretical model identifies atomic transit and absorption-induced losses as the primary factors limiting squeezing preservation. Experimentally, we engineer the atomic ensemble as a medium with tunable transmittance by employing Doppler-matched velocity-selective excitation to suppress absorption, achieving a squeezing transmission of 90.4 $$\%$$ % for -1.7 dB squeezed light through a cesium vapor cell. This work is a critical step towards quantum-enhanced Rydberg atom sensors.

PhotoniXDec 15, 20255 citations

Electromagnetically induced transparency of Rydberg atoms in modulated laser fields

Yang Zhi-Wei, Jiao Yue-Chun, Xiaoxuan Han +2 more

Rydberg atoms, with large principal quantum number n, have been widely investigated in recent years due to their peculiar properties, such as big sizes, long lifetimes and strong interactions with fields and other Rydberg atoms. Rydberg atoms are very sensitive to external fields due to their large polarizabilities scaling as n7.These make Rydberg atoms an ideal candidate for the quantum information, the many-body interaction, etc.In this work, we investigate the Rydberg atoms using electromagneticlly induced transparency (EIT) in a ladder three-level system. The EIT is a quantum interference effect between two excitation path-ways driven by two laser fields. The main idea is performed in a room temperature cesium vapor cell, where the probe laser frequency is modulated. The ground state (6P1/2), excited state (6P3/2), and Rydberg state (nS1/2) constitute a Rydberg three-level system, in which the probe laser is fixed to the 6S1/2 (F = 4)6P3/2 (F = 5) transition by saturated absorption spectrum technique, whereas the coupling laser is scanned across the 6P3/249S1/2 transition. We detect the demodulated EIT signal with the lock-in amplifier (SR830). The modulated EIT signal shows a two-peak structure. The measured spacing between two peaks increases with the frequency detuning, caused by the modulation amplitude, and half the spacing between the peak-to-peak is nearly 1.67 times the modulation amplitude of the probe laser; the measured result shows that the splitting is independent of the modulation frequency. The experimental results are in agreement with the theoretical calculations. The results in our work can be used for real-time monitoring of the laser-line profiles and the fluctuation of laser frequency.Rydberg atoms, with large principal quantum number n, have been widely investigated in recent years due to their peculiar properties, such as big sizes, long lifetimes and strong interactions with fields and other Rydberg atoms. Rydberg atoms are very sensitive to external fields due to their large polarizabilities scaling as n7.These make Rydberg atoms an ideal candidate for the quantum information, the many-body interaction, etc.In this work, we investigate the Rydberg atoms using electromagneticlly induced transparency (EIT) in a ladder three-level system. The EIT is a quantum interference effect between two excitation path-ways driven by two laser fields. The main idea is performed in a room temperature cesium vapor cell, where the probe laser frequency is modulated. The ground state (6P1/2), excited state (6P3/2), and Rydberg state (nS1/2) constitute a Rydberg three-level system, in which the probe laser is fixed to the 6S1/2 (F = 4)6P3/2 (F = 5) transition by saturated absorption spectrum technique, whereas the coupling laser is scanned across the 6P3/249S1/2 transition. We detect the demodulated EIT signal with the lock-in amplifier (SR830). The modulated EIT signal shows a two-peak structure. The measured spacing between two peaks increases with the frequency detuning, caused by the modulation amplitude, and half the spacing between the peak-to-peak is nearly 1.67 times the modulation amplitude of the probe laser; the measured result shows that the splitting is independent of the modulation frequency. The experimental results are in agreement with the theoretical calculations. The results in our work can be used for real-time monitoring of the laser-line profiles and the fluctuation of laser frequency.

Acta Physica SinicaJan 1, 20162 citations

Electromagnetically induced transparency in modulated laser fields

Yuechun Jiao, Zhiwei Yang, Hao Zhang +4 more

Abstract We study electromagnetically induced transparency (EIT) in a room-temperature cesium vapor cell using wavelength-modulated probe laser light. In the utilized cascade level scheme, the probe laser drives the lower transition 6 S 1 / 2 ( F = 4) → 6 P 3 / 2 ( F ’ = 5), while the coupling laser drives the Rydberg transition 6 P 3 / 2 → 57 S 1 / 2 . The probe laser has a fixed average frequency and is modulated at a frequency of a few kHz, with a variable modulation amplitude in the range of tens of MHz. The probe transmission is measured as a function of the detuning of the coupling laser from the Rydberg resonance. The first-harmonic demodulated EIT signal has two peaks that are, in the case of large modulation amplitude, separated by the peak-to-peak modulation amplitude of the probe laser times a scaling factor λ p / λ c , where λ p and λ c are the probe- and coupling-laser wavelengths. The scaling factor is due to Doppler shifts in the EIT geometry. Second-harmonic demodulated EIT signals, obtained with small modulation amplitudes, yield spectral lines that are much narrower than corresponding lines in the modulation-free EIT spectra. The resultant spectroscopic resolution enhancement is conducive to improved measurements of radio-frequency (RF) fields based on Rydberg-atom EIT, an approach in which the response of Rydberg atoms to RF fields is exploited to characterize RF fields. Here, we employ wavelength modulation spectroscopy to reduce the uncertainty of atom-based frequency and field measurement of an RF field in the VHF radio band.Abstract We study electromagnetically induced transparency (EIT) in a room-temperature cesium vapor cell using wavelength-modulated probe laser light. In the utilized cascade level scheme, the probe laser drives the lower transition 6 S 1 / 2 ( F = 4) → 6 P 3 / 2 ( F ’ = 5), while the coupling laser drives the Rydberg transition 6 P 3 / 2 → 57 S 1 / 2 . The probe laser has a fixed average frequency and is modulated at a frequency of a few kHz, with a variable modulation amplitude in the range of tens of MHz. The probe transmission is measured as a function of the detuning of the coupling laser from the Rydberg resonance. The first-harmonic demodulated EIT signal has two peaks that are, in the case of large modulation amplitude, separated by the peak-to-peak modulation amplitude of the probe laser times a scaling factor λ p / λ c , where λ p and λ c are the probe- and coupling-laser wavelengths. The scaling factor is due to Doppler shifts in the EIT geometry. Second-harmonic demodulated EIT signals, obtained with small modulation amplitudes, yield spectral lines that are much narrower than corresponding lines in the modulation-free EIT spectra. The resultant spectroscopic resolution enhancement is conducive to improved measurements of radio-frequency (RF) fields based on Rydberg-atom EIT, an approach in which the response of Rydberg atoms to RF fields is exploited to characterize RF fields. Here, we employ wavelength modulation spectroscopy to reduce the uncertainty of atom-based frequency and field measurement of an RF field in the VHF radio band.

Journal of Physics B Atomic Molecular and Optical PhysicsDec 19, 20161 citation

Dispersive microwave electrometry using Zeeman frequency modulation spectroscopy of electromagnetically induced transparency in Rydberg atoms

Feng-Dong Jia, Yonghong Yu, Xiubin Liu +7 more

We herein developed and demonstrated a Zeeman frequency modulation scheme for improving the signal-to-noise ratio of microwave electric field measurement using Rydberg atoms. The spectra of the electromagnetically induced transparency (EIT) and Autler-Townes splitting of Rydberg atoms is frequency modulated by an alternating current magnetic field. The signal-to-noise ratio of the corresponding dispersive error signal is enhanced more than 10 times than that of the original spectrum. Furthermore, we show that the slope of the dispersive error signal near the resonance of the Rydberg EIT can be used to characterize the weak microwave electric field amplitudes. The more intuitive and simpler structure compared with other existing frequency modulation technologies greatly reduces the difficulties of experiments and experimental data analysis.We herein developed and demonstrated a Zeeman frequency modulation scheme for improving the signal-to-noise ratio of microwave electric field measurement using Rydberg atoms. The spectra of the electromagnetically induced transparency (EIT) and Autler-Townes splitting of Rydberg atoms is frequency modulated by an alternating current magnetic field. The signal-to-noise ratio of the corresponding dispersive error signal is enhanced more than 10 times than that of the original spectrum. Furthermore, we show that the slope of the dispersive error signal near the resonance of the Rydberg EIT can be used to characterize the weak microwave electric field amplitudes. The more intuitive and simpler structure compared with other existing frequency modulation technologies greatly reduces the difficulties of experiments and experimental data analysis.

Applied OpticsAug 25, 202021 citations

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% for -1.7 dB squeezed light through a cesium vapor cell. This work is a critical step towards quantum-enhanced Rydberg atom sensors.