Work

Fluorescence imaging of nonlinear x-ray propagation and lasing

Year: 2025

Type: article

Abstract: We introduce a general approach for probing nonlinear x-ray propagation by imaging secondary fluorescence emitted transverse to the driving field. When a short, intense x-ray pulse excites a deep 1 s core orbital, subsequent K α emission from spin-orbit-split 2 p states can undergo stimulated amplification. This nonlinear process reshapes the relative populations of the 2 p 1 / 2 and 2 p 3 / 2 levels along the propagation path, leaving distinct signatures in the delayed L-edge fluorescence. By solving the coupled density-matrix and Maxwell equations, we show that these fluorescence signals provide a direct and experimentally accessible probe of x-ray amplification dynamics. We demonstrate the concept for argon atoms and extend it to molecular systems containing third-row elements, where competing effects of lifetimes, transition intensities, and nonresonant absorption determine the efficiency of stimulated emission. Our results establish L-edge fluorescence as a broadly applicable diagnostic of nonlinear x-ray phenomena, opening opportunities for studying light-matter interactions in regimes where direct detection of amplified x-ray signals is technically challenging.

Source: Physical Review Research

DOI: 10.1103/5b65-yjmp

Authors: Svyatoslav Blinov, Pavel Krasnov, Faris Gelmukhanov, Jan-Erik Rubensson, Sergey Polyutov, Victor Kimberg

Institutions: Siberian Federal University, Federal Medical-Biological Agency, KTH Royal Institute of Technology, Uppsala University

Language: English

Topic: X-ray Spectroscopy and Fluorescence Analysis

Subfield: Radiation

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $2,625

Funders: Carl Tryggers Stiftelse för Vetenskaplig Forskning, Vetenskapsrådet, Russian Science Foundation