Electromagnetically Induced Transparency Of Rydberg Atoms In The Modulation Field

Rydberg atom is a atom with big principal quantum number n.Rydberg atom,has been widely studied,due to its unique properties,such as the large sizes?ⁿ²?,long lifetimes?ⁿ³?,strong interactions(ⁿ¹¹)and so on.In particular,the characteristic of large polarizability?ⁿ⁷?makes the Rydberg atom very sensitive to the external field.Electromagnetically induced transparency?EIT?of Rydberg atoms can be used for all optical non-destructive detection of Rydberg atoms,and it is of great significance in the study of quantum logic gates and single photon sources.The Rydberg EIT provides a more accurate method for external field measurement,which has good application prospects.In this work,the probe laser couples 6S_1/2?F=4??6P_3/2?F'=5?transition and the coupling laser is scanned across the 6P_3/2?F'=5??n S/n D Rydberg transition,the Rydberg EIT signal is detected by the Photodetector?PD?.The main contents of this paper include three aspects:Firstly,the frequency locking of 510nm laser based on Rydberg EIT.Secondly,Rydberg EIT in the modulated probe laser field.Thirdly,EIT effect of the Rydberg atom in the RF field?40¹00MHz?.RF-dressed Rydberg EIT spectra provide a new method to accurately measure the RF field.Details are as follows:First,510nm laser frequency locking;In the Rydberg three-level system,the probe laser is locked to the transition6S_1/2?F=4??6P_3/2?F'=5?with the saturation absorption spectrum.We obtain the error signal by demodulating Rydberg EIT signal,the laser frequency is locked to the Rydberg transition with the PID feedback loop,the frequency fluctuation is 0.7MHz,and corresponding Allen variance of the minimum value is 8.9×10^-11.Second,the Rydberg EIT in the modulated probe laser field;Based on the Rydberg EIT in a room temperature cesium vapor cell,when a modulation of several k Hz is applied to the probe frequency,The demodulated EIT signal splits into two peaks and the measured result shows that the splitting is independent of the modulation frequency and is proportional to the magnitude of the detuning?frequency modulation amplitude?caused by the modulation amplitude.The half of the double peak interval is equal to 1.67 times the amplitude of the probe frequency modulation.The experimental results are consistent with theoretical calculations.The results of this study can be applied to real-time monitoring of laser line type and frequency jitter.Third,the RF electric field modulation of the Rydberg EIT;The EIT spectrum involving 48D_5/2 Rydberg atom in RF field undergoes AC Stark shift and splitting and sidebands.The even sidebands are consistent with the results of Floquet's theoretical simulation.the Stark spectrum of m_j=5/2 intersects with the secondary sidebands of m_j=1/2,3/2.These intersections provide a new method for calibrating RF electric field.Innovations in this article:1.We modulated the probe laser frequency and obtained two kinds of frequency error signals.One derived from the demodulation of the saturation absorption spectrum,used to lock the 852nm laser frequency;The other is from the demodulation of EIT signal,used to lock the 510nm laser frequency.Using Rydberg EIT,we lock the laser frequency to the transition of two excitation levels,the frequency fluctuation is 0.7MHz.2.Two-photon excitation and the corresponding energy level form a Rydberg EIT system.The probe laser impose a few k Hz modulation,the demodulation of the EIT signal split into two peaks.The splitting is proportional to the magnitude of probe laser modulation but not the modulation frequency.The half of the bimodal interval is equal to 1.67 times the amplitude of the probe frequency modulation.The experimental results are consistent with theoretical calculations.The results of this study can be applied to real-time monitoring of laser line type and frequency jitter.3.Rydberg atoms,having a very large polarization,is very sensitive to the external electric field.Applying the RF field,Rydberg level is modulated leading to AC Stark shift and RF sidebands.The effect of RF electric field on the Rydberg energy level was studied by Rydberg EIT.In the Stark spectrum of the weak radio frequency,the Stark spectrum of m_j=5/2 intersects with the secondary sidebands of m_j=1/2,3/2,and these energy level intersections provide an atomic-based precision a new method of calibrating RF electric field.