Theoretical Investigation of $^{41}$K States Behavior under Strong Magnetic Field and $\pi$ Polarized Laser Field

TL;DR

This paper provides a theoretical analysis of $^{41}$K atomic transitions under strong magnetic and laser fields, revealing the persistence of certain transitions and the onset of the Hyperfine Paschen-Back regime at relatively low magnetic fields.

Contribution

It introduces a detailed theoretical model of $^{41}$K's behavior under strong magnetic fields, identifying guiding transitions and the low-field onset of the Hyperfine Paschen-Back regime.

Findings

Identification of guiding transitions with stable probabilities and slopes

Observation of the Hyperfine Paschen-Back regime at B ~ 200 G

Reduction of observable transitions from 12 to 8 in D1 line and from 20 to 8 in D2 line at high B

Abstract

Theoretically research of the behavior of $^{41}$K $D_1$ and $D_2$ lines for $\pi$ polarized resonant light is conducted in the presence of strong magnetic field when the total electronic angular momentum $J$ and nuclear spin $I$ are decoupled. We show that in the case of linear polarization and for D1 line there are two transitions, so called guiding transitions (GT) that maintain their probabilities and frequency slopes. In Hyperfine Paschen-Back (HPB) regime other transitions are coming together to those GTs, making 2 groups (4 in each). Each transition in the group has the same frequency slope and probability as the GT in their group. It is demonstrated that from 12 ($D_1$) and 20 ($D_2$) initially allowed Zeeman transitions (taking into account the selection rules) at low B-field, only 8 transitions in each $D$ line remain in absorption spectra at $B > 200$ G. A complete HPB regime for relatively low magnetic fields $B \sim 200$ G has been observed. This value is the smallest for all alkali metals.