Significant modification of the spectrum of the D1 line of <sup>85</sup>Rb in optical cells with high quality antirelaxation coating on the walls is studied experimentally and theoretically analyzed. The spectral profiles of hyperfine transitions are found to be significantly dependent on the velocity and the direction of the laser frequency scanning. A physical explanation is proposed for the observed features, which is confirmed by numerical simulations. The effect of small magnetic field on hyperfine spectrum is also discussed.
We report some preliminary results on experimental investigation of the potential of Light Induced Atomic Desorption (LIAD) applications for density control in antirelaxation coated cells and coherent spectroscopy. LIAD is a non-thermal process whereby atoms adsorbed on a surface are released under illumination. It is applied mostly to implementing optical atomic dispensers in the cases when high atomic density at low temperature is needed - for example, for loading atomic devices as atomic magnetometers, atomic clocks, atomic traps and their miniaturization. An advantage of the light control is that it is faster than the temperature control. More than an order of increase of the density with LIAD is obtained. Some peculiarities in the 780 nm absorption and fluorescence spectra registered in dense Rb vapor are registered. The absorption and fluorescence spectra in Rb vapors controlled by temperature and LIAD are compared.
COSMA: Coherent Optics Sensors for Medical Application is an European Marie Curie Project running from 2012 to March 2016, with the participation of 10 teams from Armenia, Bulgaria, India, Israel, Italy, Poland, Russia, UK, USA. The main objective was to focus theoretical and experimental research on biomagnetism phenomena, with the specific aim to develop all-optical sensors dedicated to their detection and suitable for applications in clinical diagnostics. The paper presents some of the most recent results obtained during the exchange visits of the involved scientists, after an introduction about the phenomenon which is the pillar of this kind of research and of many other new fields in laser spectroscopy, atomic physics, and quantum optics: the dark resonance.
The dynamics of Light-Induced Atomic Desorption (LIAD) in 6 cells with different coatings (PDMS coated cells prepared with two different concentrations of PDMS in ether, SC-77, PCHS, DCDMS, OTS) is investigated. The rates of desorption and adsorption of the Rb atoms when the illuminating light is switched ON and OFF and their dependence on the illuminating blue-light power are measured. The influence of the homogeneity of illumination for increasing the desorption and adsorption rates is evaluated. The results are interesting for the better understanding of LIAD and its dynamics and for the development of new optoelectronic elements, LIAD-loaded atomic devices and their miniaturization, and new methods for surface and coating diagnostics.
In this work we present new features observed in the Saturated Absorption (SA) spectrum on the D<sub>1</sub> line of K. In an
uncoated optical glass cell containing pure K atoms, excitation by circularly polarized pump beam produces an
enhancement of the amplitude of the crossover resonances due to the hyperfine transitions starting from the ground state
F<sub>g</sub> = 2. This effect appears to be much more relevant when K atoms are contained in a cell coated with an anti-relaxation
film. Here, the crossover resonance in the F<sub>g</sub> = 2 set of transition is not observed experimentally with linearly polarized
pump light, while in case of circular polarization its amplitude is significantly enlarged. The Light Induced Atomic
Desorption (LIAD) effect strongly improves the intensities of the SA resonances observed in coated cell.