A new method for spatial mode shifting of a stabilized optical cavity for the generation of dual-color X-rays

TL;DR

This paper introduces a novel method to actively shift the focal point of a stabilized optical cavity using mirror rotation, enabling rapid dual-color X-ray generation via Inverse Compton Scattering.

Contribution

The paper presents a new technique for spatially shifting a stabilized optical cavity's focal point with high speed, facilitating dual-color X-ray production through cavity manipulation.

Findings

Achieved a 135 μm shift in 50 ms while maintaining cavity resonance.

Demonstrated the feasibility of switching focal points for dual-energy X-ray generation.

Proposed a cavity arrangement for sequential dual-color X-ray bursts.

Abstract

We propose an innovative method to shift the transversal position of the focal point of an optical cavity keeping it actively stabilized. Our cavity is a 4 mirrors bow-tie cavity and the spatial shift of the resonant mode is obtained by properly rotating the two curved mirrors by piezo actuators. This method allows us to move the transversal position of the cavity focal point of $135 \mu m$ in a time of $50 ms$, keeping the resonance condition of the cavity by means of the Pound-Drever-Hall technique. We propose to use this technique for the generation of 2-color X-rays via Inverse Compton Scattering (ICS). This technique exploits the large average power stored in the high finesse cavity by shifting the laser beam with respect to the electron beam trajectory, hence controlling the spatial superposition of the electron and photon beams in the interaction region. Arranging two cavities assembled one on top of the other, with different collision angle with the electron beam, allows the generation of X-ray bursts of different energies just by swiftly moving the two cavities, switching the two focal points onto the electron beam trajectory, thus activating in sequence two different ICS spectral lines.