Lifetime assessment of RbN-filled MEMS atomic vapor cells with AlO coating.

Micro-fabricated (MEMS) alkali vapor cells are at the heart of the miniaturization of atomic devices such as atomic magnetometers, atomic gyroscopes and atomic clocks. Among the different techniques used to fill microfabricated alkali vapor cell, UV decomposition of rubidium azide (RbN) into metallic Rb and nitrogen in AlO coated cells is a very promising approach for low-cost wafer-level fabrication. Here we present a detailed lifetime study of such cells.

Quantitative Micro-Raman Spectroscopy for Partial Pressure Measurement in Small Volumes.

We demonstrate the quantitative capabilities of Raman confocal microscopy as a nondestructive method to measure the partial pressure of molecular gases in mm range sealed volume having an optical access. Thanks to a calibration procedure, we apply this technique for the characterization of the absolute nitrogen partial pressure inside buffered micro electromechanical system (MEMS) atomic vapor cells developed for atomic clocks. Our results are compared with measurements obtained by rubidium hyperfine frequency spectroscopy and a good agreement is demonstrated between the two methods, with a three-sigma detection limit below 10 mbar for a 1 h integration time, using a 33 mW 532 nm excitation laser.

1,4-dimethylenespiropentane: a unique model system for studying Fermi resonance in Raman optical activity.

The C(2)-symmetric title compound, a small, rigid hydrocarbon molecule with two distinct, strongly interacting vibrational chromophores, represents a unique model system for testing computational approaches to Raman optical activity (ROA) beyond the isolated molecule and the harmonic approximation. We show that the experimental Raman and ROA spectra are marked by the presence of strong Fermi resonances, and that the shape and relative size of the bands which we attribute to such resonances strongly depend on the solvent environment of the molecule. On the other hand, the dominant computed ROA couplet, arising from the C=C stretching vibrations, is absent in the spectra measured in the condensed phase.