From self-organization in relativistic electron bunches to coherent synchrotron light: observation using a photonic time-stretch digitizer

Abstract

In recent and future synchrotron radiation facilities, relativistic electron bunches with increasingly high charge density are needed for producing brilliant light at various wavelengths, from X-rays to terahertz. In such conditions, interaction of electron bunches with their own emitted electromagnetic fields leads to instabilities and spontaneous formation of complex spatial structures. Understanding these instabilities is therefore key in most electron accelerators. However, investigations suffer from the lack of non-destructive recording tools for electron bunch shapes. In storage rings, most studies thus focus on the resulting emitted radiation. Here, we present measurements of the electric field in the immediate vicinity of the electron bunch in a storage ring, over many turns. For recording the ultrafast electric field, we designed a photonic time-stretch analog-to-digital converter with terasamples/second acquisition rate. We could thus observe the predicted link between spontaneous pattern formation and giant bursts of coherent synchrotron radiation in a storage ring.

Revealing the dynamics of ultrarelativistic non-equilibrium many-electron systems with phase space tomography

“…With respect to MBI, the electron bunch might be regarded as a non-equilibrium thermodynamic system with a steady flow of energy exhibiting rich structural and dynamic self-organized patterns 12 similar to other non-equilibrium thermodynamic systems, such as the Rayleigh–Bérnard convection, Turing instability or the Belousov–Zhabotinsky reaction 13 . Here, a deep understanding of the physical laws determining the development of the electron bunch density bears the potential to further control or stabilize the occurrence of the CSR bursts, which then could provide a bright THz radiation source for user applications 14 .…”

Advanced diagnostic detectors for rogue phenomena, single-shot applications

“…7 for a review). These technologies have opened up new frontiers in measurement science: in nonlinear dynamics of optical rogue waves, 8 acoustic shock waves, 9 mode-locked lasers, [10][11][12][13][14][15][16][17] parametric oscillators, 18 relativistic electron bunching, 6,19 as well as in applications to cancer cell identification, 20,21 optical coherence tomography (OCT), 22,23 material pump-probe spectroscopy, 24 and LIDAR. 25 To satisfy the ever-increasing demands on high-performance detectors for future physics experiments, at Karlsruhe Institute of Technology (KIT) several new detector technologies and systems are continuously developed in close collaboration with beam physics scientists of Karlsruhe Research Accelerator (KARA), 26 DESY 27 and Lille University.…”

A Unified Framework for Photonic Time‐Stretch Systems

“…[ 1,4–15 ] In the ensuing two decades, it has emerged as the most successful approach to real‐time measurements and has mutated into many variants for diverse applications including spectroscopy, imaging, vibrometry, velocimetry, radar, and lidar. [ 3 ] Time stretch has enabled the discovery of single‐shot ultrafast “rare events” such as optical rogue waves, [ 16–23 ] the birth of laser mode‐locking and internal dynamics of soliton molecules, [ 24–43 ] relativistic electron dynamics in an electron accelerator, [ 44–47 ] and dynamic chemistry during combustion. [ 48 ] Time stretch has been employed in ultrafast spectroscopy for exploring dynamical processes and nonrepetitive phenomena.…”

“…[1,[4][5][6][7][8][9][10][11][12][13][14][15] In the ensuing two decades, it has emerged as the most successful approach to real-time measurements and has mutated into many variants for diverse applications including spectroscopy, imaging, vibrometry, velocimetry, radar, and lidar. [3] Time stretch has enabled the discovery of single-shot ultrafast "rare events" such as optical rogue waves, [16][17][18][19][20][21][22][23] the birth of laser modelocking and internal dynamics of soliton molecules, [24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43] relativistic electron dynamics in an electron accelerator, [44][45][46][47] and dynamic chemistry during combustion. [48] Time stretch...…”