Coherent generation and control of electro-magnetic fields in atomic systems

Seth Merkel, Souma Chaudhury, Poul Jessen +1 more

Lei Wang, 杨庆禹, 王潇潇 +7 more

We experimentally study the controllable generation of a beating signal using stored light pulses based on electro- magnetically induced transparency （EIT） in a solid medium. The beating signal relies on an asymmetric procedure of light storage and retrieval. After storing the probe pulse into the spin coherence under the EIT condition, two-color control fields with opposite detunings instead of the initial control field are used to scatter the stored spin coherence. The controllable beating signal is generated due to alternative constructive and destructive interferences in the retrieved signal intensities. The beating of the two-color control fields is mapped into the beating of weak probe fields by using atomic spin coherence. This beating signal will be important in precise atomic spectroscopy and fast quantum limited measurements.

Warren S. Warren

Yong Hu, Y. Y. Feng, Chi Xu +2 more

We have set up a coherent population trapping (CPT)-based magnetometer prototype with the D1 line of ⁸⁷Rb atoms. The dichromatic light field is derived from a fiber electro-optic modulator (FEOM) connected to an external cavity laser diode. A CPT resonance signal with a 516 Hz linewidth is observed. By feeding back the derivative of the resonance curve to the FEOM with a proportional integral controller, of which the voltage output is directly converted to the measured magnetic field intensity, the resonance peak is locked to the environmental magnetic field. The measurement data we have achieved are well matched with the data measured by a commercial fluxgate magnetometer within 2 nT, and the sensitivity is better than 8 pT/√Hz in a parallel B field.

Thanh Thai Doan, Hoang Minh Dong

Abstract Magnetic field plays an important role in studying the transient response because the transition probabilities of degenerate energy levels depend on the external field. The application of an external magnetic field is of particular interest, as the magnetic field is readily available and more flexible to control than an additional laser field, which is an essential consideration in our paper. In this work, we propose a simple model for managing the transient absorption and dispersion properties in a degenerate two-level atomic medium under both transparency and absorption regimes in the presence of spontaneously generated coherence (SGC), an incoherent pumping field, and an external magnetic field. We show that a magnetic field can be utilized as a ‘knob’ to swap the transient absorption and dispersion properties of the system in both transparency and absorption regimes. The magnetic field not only aids in creating transparency and absorption regimes but is also helpful in controlling the system operating at different frequency regions for the probe field without changing the frequency of the coupling field; SGC is introduced to enhance the laser phase dependence of the atomic optical properties, while the incoherent pumping field plays a role in enhancing the effects of SGC and relative phase on the atomic optical properties. The influences of SGC, relative phase, and incoherent pumping rate on transient response are also considered to improve the stability of transient absorption and dispersion properties. Moreover, the essential time required for swapping between subluminal and superluminal light propagation is also provided. The proposed model shows that the system can be used as an ultrafast optical switch, which, in practice, may enable control over switching rates in quantum storage and information-processing devices.

Dimitrios Charalambidis, Natalia E. Karapanagioti, D. Xenakis +8 more