Laser Spectroscopy with Nanometric Cells Containing Atomic Vapor of Metal: Influence of Buffer Gas

Comparison of absorption and fluorescence in a nano-cell containing Rb vapor with other Rb nano-cells where neon gas is added is presented. The effect of collapse and revival of Dicke-type narrowing is still observable for the Rb nano-cells where Ne gas is added under 6 and 20 Torr pressure for the thickness L=/2 and L=, where  is a resonant laser wavelength 794 nm (D1 line). Particularly for 6 Torr the line-width of the transmission spectrum for the thickness L=/2 is 2 times narrower than that for L=. 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=, VSOP resonances located at the atomic transition are still observable even when Ne pressure is ≥ 6 Torr. Narrowband fluorescence spectra of the 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 Rb with another nano-cell, where buffer gas nitrogen is added, is presented. Use of gas N2 inside the Rb nanocell strongly extended the region of the coupling laser detuning where EIT resonance is still possible to form.