Polarization spectroscopy and magnetically-induced dichroism of the potassium D2 lines

TL;DR

This paper investigates polarization spectroscopy and magnetically-induced dichroism of potassium D2 lines, proposing a modified scheme with spatially separated beams to improve laser stabilization signals.

Contribution

It introduces a novel modified magnetically-induced dichroism scheme with spatially separated pump-probe beams for better sub-Doppler line shape detection.

Findings

Polarization spectroscopy provides clear sub-Doppler dispersive signals.

The modified scheme reduces background offset and enhances dispersion.

Comparison shows advantages over phase modulation and heterodyne detection methods.

Abstract

We study modulation-free methods for producing sub-Doppler, dispersive line shapes for laser stabilization near the potassium D2 transitions at 767 nm. Polarization spectroscopy is performed and a comparison is made between the use of a mirror or beam splitter for aligning the counter-propagating pump and probe beams. Conventional magnetically-induced dichroism is found to suffer from a small dispersion and large background offset. We therefore introduce a modified scheme, using two spatially separated pump-probe beam pairs. Finally we compare our results to methods using phase modulation and heterodyne detection.