Frequency stabilization method for transition to a Rydberg state using Zeeman modulation

Abstract

We herein develop and demonstrate a stable frequency-locking scheme for Rydberg atomic experiments. We use the Zeeman effect to modulate the three-level ladder-type Rydberg electromagnetically induced transparency (EIT) signal to lock the laser frequency of the coupling light for transition from its intermediate state to a Rydberg state. The effects of polarization of the probe and coupling lights, and the amplitude of the AC modulated magnetic field B 0 on the EIT and the corresponding dispersive error signal, are both analyzed. The results show that both the EIT signal and dispersive error signal are the strongest when the polarizations of coupling and probe fields are circular and equal. The signal-to-noise ratio of the dispersive error signal increases with B 0 . The slope of the dispersive error signal increases first and then decreases with B 0 , which is related to the increase of the EIT linewidth caused by the higher B 0 . The linewidth of the laser is significantly less than 500 kHz after frequency locking, which satisfies the requirements of most experiments involving Rydberg atoms. The method proposed herein can generally be applied to any cascade system of Rydberg atoms.

An all-optical phase detector by amplitude modulation of the local field in a Rydberg atom-based mixer

“…[24] A relatively stronger coupling light with λ c = 480 nm was generated using a frequency-doubled diode laser (TA-SHG-Pro, Toptica), and the frequency was locked on the resonance transition of |2 to |3 using the Zeeman modulation Rydberg EIT spectrum. [25] The linewidths of all the lasers were estimated to be less than 500 kHz using the linewidth of the Rydberg EIT with 494 kHz in cold atom samples. [25] The minimum Allen variance σ (𝜏 ) laser of lasers was approximately 7.3 × 10 −11 at 8 s for laser stabilization.…”

“…[25] The linewidths of all the lasers were estimated to be less than 500 kHz using the linewidth of the Rydberg EIT with 494 kHz in cold atom samples. [25] The minimum Allen variance σ (𝜏 ) laser of lasers was approximately 7.3 × 10 −11 at 8 s for laser stabilization. [26] The probe light was focused to an 800 µm 1/ e 2 diameter using an achromatic lens with power I p = 25 µW.…”

Laser frequency locking method for Rydberg atomic sensing

“…One is locking the laser frequency to an external optical reference cavity, such as the Pound-Drever-Hall (PDH) method [10][11][12][13][14] . The other is using atomic transition spectroscopy for laser frequency stabilization, such as saturated absorption spectroscopy (SAS) [15] , polarization spectroscopy [16] , modulation transfer spectroscopy [17] , and recently, EIT spectroscopy [18][19][20] . The cavity-locking methods are susceptible to environmental factors such as pressure and temperature and require additional means to shift the laser frequency to the atomic resonance transition, since the reference is the cavity rather than the atomic level.…”

1.6 GHz Frequency Scanning of a 482 nm Laser Stabilized Using Electromagnetically Induced Transparency

“…In addition, techniques such as electromagnetically induced transparency (EIT) or beat note locking can be used to lock the relative frequency of two lasers [6]- [10]. The first method is widely employed in situations where it is difficult to obtain a direct absorption signal, such as the excitation of a neutral atom to a Rydberg level using a cascaded process [11]- [13]. The disadvantage of this technique is that it tends to provide discrete frequency reference shifts.…”