Comparison of absorption and fluorescence in a nano-cell containing Rb vapor with other Rb nano-cells with addition of neon gas is presented. It is shown that the effect of collapse and revival of Dicke-type narrowing occurs for Rb nanocells containing N2 as buffer gas under 6 and 20 Torr pressure for the thickness L = λ /2 and L = where λ is the resonant λ, laser wavelength 794 nm (D1 line). Particularly for 6 Torr the line-width of the transmission spectrum for the thickness L =λ/2 is 2 times narrower than that for L = λ. For an ordinary Rb cell with L = 0.1 - 10 cm with addition of buffer gas, the velocity selective optical pumping/saturation (VSOP) resonances in saturated absorption spectra are fully suppressed when the buffer gas pressure > 0.5 Torr. A spectacular difference is that for L = λ, VSOP resonances located at the atomic transitions are still observable even when Ne pressure is ≥ 6 Torr. Narrowband fluorescence spectra of a nano-cell with L = λ/2 can be used as a convenient tool for online buffer gas pressure monitoring for the conditions when ordinary pressure gauges are unusable. Comparison of electromagnetically induced transparency (EIT) effect in a nano-cell filled with pure (without a buffer gas) Rb with another nano-cell, where buffer gas nitrogen is added, is presented. The use of N2 gas inside Rb nano-cells strongly extends the range of coupling laser detunings in which it is still possible to form EIT resonance.
Comparison of absorption and fluorescence in a nano-cell containing Rb vapor with other Rb nano-cells with addition of neon gas is presented. It is shown that the effect of collapse and revival of Dicke-type narrowing occurs for Rb nanocells containing N2 as buffer gas under 6 and 20 Torr pressure for the thickness L = λ /2 and L = where λ is the resonant λ, laser wavelength 794 nm (D1 line). Particularly for 6 Torr the line-width of the transmission spectrum for the thickness L =λ/2 is 2 times narrower than that for L = λ. For an ordinary Rb cell with L = 0.1 - 10 cm with addition of buffer gas, the velocity selective optical pumping/saturation (VSOP) resonances in saturated absorption spectra are fully suppressed when the buffer gas pressure > 0.5 Torr. A spectacular difference is that for L = λ, VSOP resonances located at the atomic transitions are still observable even when Ne pressure is ≥ 6 Torr. Narrowband fluorescence spectra of a nano-cell with L = λ/2 can be used as a convenient tool for online buffer gas pressure monitoring for the conditions when ordinary pressure gauges are unusable. Comparison of electromagnetically induced transparency (EIT) effect in a nano-cell filled with pure (without a buffer gas) Rb with another nano-cell, where buffer gas nitrogen is added, is presented. The use of N2 gas inside Rb nano-cells strongly extends the range of coupling laser detunings in which it is still possible to form EIT resonance.
A new submicron thin cell (STC) filled with Rb and neon gas is developed and comparison of resonant absorption with STC containing pure Rb is provided. The effect of collapse and revival of Dicke-type narrowing is still observable for the thickness L = lambda /2 and L = lambda , where lambda is a resonant laser wavelength 794 nm (D(1) line). For an ordinary Rb cm-size cell with addition of buffer gas, the velocity selective optical pumping/saturation (VSOP) resonances in saturated absorption spectra are fully suppressed if neon pressure > 0.5 Torr. A spectacular difference is that for L = lambda , VSOP resonances are still observable even when neon pressure is > or = 6 Torr. Narrow fluorescence spectra at L = lambda /2 allow one to realize online buffer gas pressure monitoring. A good agreement with theoretical model is observed.
Comparison of the absorption and fluorescence in the nanocell (or so called extremely thin cell) filled with pure Rb with another one filled with Rb and Neon gas is provided. The effect of the collapse and revival of Dicke-type narrowing is still observable for thickness L=lambda/2, and lambda, where lambda , is a resonant laser wavelength either 780 nm, or 795 nm (for Rb, D2 or D1 line). For L= so called velocity selective optical pumping (VSOP) resonance located at the atomic transition is still observable, while the linewidth is increased by 4 times in comparison with that obtained in the pure Rb nanocell. Comparison with the theory is presented. Electromagnetically Induced Transparency effect detected in the nanocell filled with Rb and Neon gas is presented. The EIT resonance linewidth is of 12 MHz when L~ 1 µm, while for the nanocell filled with pure Rb linewidth is ~9 MHz.
Comparison of the resonant absorption and fluorescence in the extremely thin cell (ETC) filled with pure Rb with another one filled with Rb and Neon gas with the pressures 6 Torr and 20 Torr is provided. The effect of the collapse and revival of Dicke-type narrowing is still observable for the thickness L=λ/2, and L=λ, where λ is a resonant laser wavelength 794 nm (D1 line of the Rb), i.e. the spectra of the resonant absorption and fluorescence demonstrate the sub-Doppler narrowing for the thickness L=λ/2 and broadening for the thickness L=λ. It is important to note, that in an ordinary Rb cell with the thickness L in the range of 1mm- 10 cm filled with buffer gas, with a pressure higher than 1 Torr in the Saturation Absorption scheme, any sub-Doppler features are absent. For L= λ the so called velocity selective optical pumping (VSOP) resonance located at the atomic transition is still observable when Ne pressure is 6 Torr , while the linewidth is increased by 4 times in comparison with that obtained in the pure Rb ETC. This VSOP resonance is wash out when Ne pressure is 20 Torr. It is demonstrated that use of the fluorescence spectra at L=λ/2 allows one to use the ETC for the buffer gas pressure measurement. Comparison with the theory is presented.
Recently unique extremely thin cells (ETC) containing atomic vapour of alkali metals with the column thickness L of an order and much less than optical light wavelength λ have been developed. It has been demonstrated that these ETC are a very promising tool for a fundamental study of atom-light, atom-atom, atom-surface and atom-external magnetic field interactions. Particularly, a dramatically different behaviour of resonant absorption, fluorescence and resonant magneto-optical processes compared to that obtained with the help of cm-long ordinary cells has been demonstrated. Possible applications based on ETC are described, such as magnetometers with nanometric spatial resolution and tunable atomic frequency references. For the study of buffer gas influence, a multi-region cell (MRC) has been developed. MRC consists of an ETC cell having a wedged thickness of the gap between the windows that allows one to form atomic vapour column thickness in the range of 0.1 ÷ 4 μm. The ETC is connected through a sapphire tube with a 1cm-long sapphire tube having sapphire windows. The 1cm-long cell has a sapphire side-arm containing Rb metal. MRC's are filled with 6 Torr and 20 Torr Neon gas, thus there is Rb vapour and buffer gas inside the MRC. The construction of the MRC allows one to compare absorption and fluorescence processes simultaneously in the case of the ETC use as well as in the case of 1cm-long ordinary cell use. The comparison of the resonant absorption and fluorescence in the extremely thin cell (ETC) filled with pure Rb with another one filled with Rb and Neon gas with the pressures of 6 Torr and 20 Torr is provided. The effect of the collapse and revival of Dicke-type narrowing is still observable for the thicknesses L = λ/2, and L = λ, with λ being the resonant laser wavelength 794 nm (D1 line of Rb), i.e. the spectra of the resonant absorption and fluorescence demonstrate strong sub-Doppler narrowing for the thickness L = λ/2 and broadening for the thickness L = λ. It is important to note that in an ordinary Rb cell with the thickness L in the range of 1mm - 10 cm filled with buffer gas, with the pressure higher than 1 Torr, in the well-known Saturation Absorption scheme, any sub-Doppler features are absent. For L = λ the so called velocity selective optical pumping/saturating resonance (VSOP) located at the atomic transition is still observable when Ne pressure is 6 Torr, while the linewidth is increased by 4 times in comparison with that obtained in a pure Rb ETC. It is also demonstrated that the use of the fluorescence spectra at L = λ/2 allows one to use ETC for the buffer gas pressure measurements. Comparison with the theory will be presented.
Recently developed thin cells containing atomic vapor of micrometric column thickness L allow one to study peculiarities of Electromagnetically Induced Transparency (EIT) phenomenon, along with the accompanying velocity selective optical pumping/saturation (VSOP) resonances for the case when < 100 &mgr;m. The micrometric thin cells (MTC) are filled with pure Rb and neither buffer gas nor paraffin-coated walls were used. The Λ-systems on D2 line of 85Rb have been studied experimentally with the use of bi-chromatic radiation of two separate diode lasers (λ≈780 nm, γL&≈ 5MHz). It is demonstrated that when L~60 &mgr;m it is still possible to form the EIT resonance with the sub-natural linewidth ~ 5 MHz. The EIT resonance linewidth increases up to 10 MHz , when column thickness L is reduced down to ~ 2 &mgr;m. Six VSOP resonances are detected in the fluorescence and absorption spectra when the thickness L ~ 10 &mgr;m. Dependence of the EIT resonance linewidth as a function of the atomic vapor column thickness L is presented.
We studied selective reflection (SR) of laser radiation from a window of a nanocell with thickness L ~ λ 1,2 /2 filled with Rb and Cs atoms, where λ 1 = 780 nm and λ 2 = 852 nm are the wavelengths resonant with the D 2 laser lines for Rb and Cs, respectively. It is demonstrated that the negative derivative of the SR signal profile for L > λ /2 changes to the positive one for L < λ /2. It is shown that the real-time formation of the SR signal profile derivative (SRD) with the spectral width 30–40 MHz and located at the atomic transition is, in particular, a convenient frequency marker of D 2 transitions in Rb and Cs. The amplitudes of SRD signals are proportional to the atomic transition probabilities. A comparison with the known saturated absorption (SA) method demonstrated a number of advantages, such as the absence of cross-over resonances in the SRD spectrum, the simplicity of realization, a low required power, etc. An SRD frequency marker also operates in the presence of the Ne buffer gas at a pressure of 6 Torr, which allowed us to determine the Ne–Rb collisional broadening, whereas the SA method is already inapplicable at buffer gas pressures above 0.1 Torr. The realization simplicity makes the SRD method a convenient tool for atomic spectroscopy. Our theoretical model well describes the SRD signal.