Two-photon dichroic atomic vapor laser lock using electromagnetically induced transparency and absorption

Abstract

We demonstrate a technique to lock the frequency of a laser to a transition between two excited states in Rb vapor using a two-photon process in the presence of a weak magnetic field. We use a ladder configuration from specific hyperfine sublevels of the 5S 1/2 , 5P 3/2 , and 5D 5/2 levels. This atomic configuration can show Electromagnetically Induced Transparency and Absorption processes. The error signal comes from the difference in the transparency or absorption felt by the two orthogonal polarizations of the probe beam. A simplified model is in good quantitative agreement with the observed signals for the experimental parameters. We have used this technique to lock the frequency of the laser up to 1.5 GHz off atomic resonance.

Efficient generation of a narrow-bandwidth and frequency-modulated beam pair from Yb atoms in a ladder configuration

“…We also used a dispersive signal detected by a Stokes parameter detector (SPD) in Fig. 1(b) to precisely tune and stabilize c with an independent servo controller [7,8]. This dispersive signal is originated from the laser induced birefringence at ω p caused by the circularly polarized counterpropagating CL beam at ω c in the Yb hollow cathode lamp (Yb HCL) [7].…”

“…On the other hand, cascaded three-level atomic systems in various atoms have also been actively investigated, for instance, to create an atomic coherence between the ground and upper states with two coherent driving fields mediated by an intermediate state, resulting in an electromagnetically induced transparency (EIT) and absorption of the probe field [5][6][7][8][9][10]. Recently, theoretical studies relevant to the nonclassical biphoton generation in different configurations of multilevel atomic systems were reported focused on the correlation properties of the generated paired photons [11,12].…”

Probe-intensity dependence of velocity-selective polarization spectra at the rubidiumD2manifold and comparison with a rate-equation calculation

“…The development of models for describing the shape of the spectra obtained by means of the interaction between laser light and alkali atom vapors is motivated by the need of predicting both Doppler broadened and sub-Doppler spectra with high accuracy [1][2][3][4][5]. This understanding can be applied to the improvement and development of new laser stabilization techniques [6][7][8][9], laser cooling and trapping systems, chip-scale atomic clocks [10], magnetometry and inertial sensing systems [11,12], spectroscopic measurements of atomic energy levels [13], as well as in electromagnetically induced transparency (EIT) experiments [14].…”

Magneto-optical polarization rotation in a ladder-type atomic system for tunable offset locking

“…Magnetic field has previously been used in the two-photon variation of commonly employed dichroic atomic vapor laser lock setup, but exclusively to obtain the Dopplerfree steep signal itself. 19 The setup did not offer tunability of the two-photon offset frequency. Tuning capability of magnetic field has only been used so far in absorptive 20 or Faraday anomalous dispersion filters 21 based on atomic vapors.…”

“…Another method would be to simply supply the error signal as feedback to the 776 nm laser. 12,19 The setup we demonstrated could be also used to stabilize the twophoton detuning when the excitation is done in a frequencydegenerate scheme (e.g., by 778 nm light in case of 5S 1=2 ! 5D 5=2 transition), 29 possibly providing even narrower line due to perfect cancellation of Doppler-broadening, or alternatievely at transitions including telecommunication wavelengths.…”