The detection of rapid dynamics in diverse physical systems is traditionally very difficult and strongly dominated by several noise contributions. Laser mode-locking, electron bunches in accelerators, and optical-triggered phases in materials are events that carry important information about the system from which they emerge. By detecting single-shot spectra with high repetition rates over long-time scales, new possibilities and applications to diagnose, control and tailor the spectral dynamics of lasers and electron beams in synchrotron and free-electron laser (FEL) accelerators open up. This contribution focuses on the latest developments of real-time, single-shot, high-repetition-rate detectors and data acquisition systems, with a special focus on emerging technologies and new possibilities in the diagnostics of rogue optical signals.
There is an increasing need for techniques allowing a whole Terahertz spectrum (or a electric field time-evolution) to be recorded at each shot of a pulsed source. We review here the principles and performances of the recently introduced DEOS single-shot Time-Domain Spectroscopy method [1]. A key point of DEOS is a novel conceptual approach of a classic electro-optic detection method, that uses chirped laser pulse probes. This novel point of view led to a new type of design that allows a numerical reconstruction of the input THz signal, from a single-shot measurement, with unprecedented bandwidth and time-resolution. We present here the theoretical framework, experimental tests, as well as numerical investigations aiming at exploring the bandwidth and resolution limits of DEOS.
[1] Roussel et al., Light Science & Applications 11, 14 (2022) https://doi.org/10.1038/s41377-021-00696-2
KEYWORDS: Sensors, Field programmable gate arrays, Free electron lasers, Data processing, Electronics, Silicon, Synchrotrons, Analog electronics, Data acquisition, Diagnostics
KALYPSO is a novel detector operating at line rates above 10 Mfps. The detector board holds a silicon or InGaAs linear array sensor with spectral sensitivity ranging from 400 nm to 2600 nm. The sensor is connected to a cutting-edge, custom designed, ASIC readout chip, which is responsible for the remarkable frame rate. The FPGA readout architecture enables continuous data acquisition and processing in real time. This detector is currently employed in many synchrotron facilities for beam diagnostics and for the characterization of self-built Ytterbium-doped fiber laser emitting around 1050 nm with a bandwidth of 40 nm.
The Accelerator for the European X-Ray Free Electron Laser delivers femtosecond electron bunches at an energy of currently 14GeV at a repetition rate of up to 4.5MHz in bursts of up to 2700 pulses every 100ms to distribute them between different undulator beamlines. The emitted femtosecond x-ray laser pulses at wavelengths between 0.05nm and 6nm can serve up to three experiments in parallel.
To measure the longitudinal bunch profile of the electron bunches, three detection systems based on electro-optical spectral decoding have been installed and are currently being commissioned. The systems are capable of recording individual longitudinal bunch profiles of all bunches in a burst with sub-ps resolution at a bunch repetition rate of 1.1 MHz, sampling the electron Coulomb field with laser pulses at 1030nm. A short detector latency of about 10µs also gives the prerequisites to establish a fast intra-burst feedback to stabilize the bunch profile. Bunch lengths and arrival times of entire bunch trains with single-bunch resolution have been measured as well as jitter and drifts for consecutive bunch trains.
For comparison of detection techniques at one position, the laser signal is split and measured with a time-stretch setup in parallel.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.