Velocity-selective imaging using cesium-based photon detectors

J. P. Temirov, Nikolay Chigarev, Oleg I. Matveev +3 more

Yuan Li, De-Huan Cai, Rong Ma +3 more

Nathan C. Pixley, Tiffany L. Correll, Dimitri Pappas +2 more

Improvements in spectral resolution and sensitivity of a cesium based resonance fluorescence imaging monochromator (RFIM) are described. Alignment of the two lasers used in the excitation scheme in a co-propagating geometry have resulted in a detector spectral bandpass (270 MHz) that is narrower than the Doppler broadened profile (380 MHz) of cesium vapor at room temperature. Improvements in the experimental design, namely the addition of an image intensifier and cooled charge-coupled device (CCD) camera, have resulted in increased sensitivity; we report a limit of detection of 10 8 photons per pixel limited by image intensifier noise. Images of the cesium D 2 line emission (852.12 nm) from a cesium hollow cathode lamp were compared to an argon emission line (4Sº 1/2 → 4P 3/2 ) at 852.14 nm from a silver/argon hollow cathode lamp as a demonstration of the spectral resolution. The ability of the RFIM to discriminate between photons exciting the F = 4 vs. F = 3 ground state hyperfine level (a frequency difference of 9.2 GHz) of the cesium 6 2 S 1/2 state was also investigated to further demonstrate the spectral selectivity. The potential use of the described RFIM for chemical imaging applications is discussed.

Giacomo Mauro D’Ariano, Chiara Macchiavello, Matteo G. A. Paris

Ravinder Kachru, THOMAS W. MOSSBERG, Sven R. Hartmann

Nathan C. Pixley, Tiffany L. Correll, Dimitri Pappas +3 more

A cesium-based resonance fluorescence monochromator with a spectral resolution of 200 MHz and a tunable response over the D(2) absorption line of cesium (380 MHz) is described. The narrow spectral response is achieved through excitation of a monokinetic population of the 6(2)P(3/2)( degrees ) state by arrangement of the excitation lasers in either a copropagating or a counterpropagating orientation. The narrow spectral response of the detector allows for excitation of specific hyperfine components involved in the 6(2)P(3/2)( degrees ) (F=3-5) to 6(2)D(5/2) (F=2-6) transition (917.23 nm). The selectivity gained through resolving specific hyperfine transitions allows for a photon detector that is both spectrally tunable and narrow. We report the sub-Doppler linewidths achieved through various laser beam orientations. We also describe how these beam geometries can be applied to spectrally narrow and tunable image detection.