arXiv subjects

Cristian Barbero

Publications and source records attributed to Cristian Barbero.

3 recordsLinked to original sources

arXiv2026

Analysis of phase instabilities in amplitude swing for ultrashort pulse train characterization

The temporal dynamics of ultrashort pulses are a fundamental feature in ultrafast optics. These dynamics can often be extracted from a two-dimensional trace consisting of a set of nonlinear spectra, using an iterative algorithm. Typically, the measurement of this trace requires integrating the signal of many pulses, which implies that the trace does not correspond to a single pulse when shot-to-shot variations occur. In this case, the pulse train can be characterized statistically, by a base pulse and a metric that quantifies the instabilities. Here, we demonstrate that the amplitude swing technique is sensitive to instabilities, which manifest as two distinct imprints on the measurement. First, we analyze the terms that compose the amplitude swing signal. Then, we study two parameters to quantify the instabilities, related to a shift in the minima of the trace marginal, and to the filling of the trace minima zones, respectively. Finally, we apply these strategies to characterize simulated unstable pulse trains, using a simple technique.

physics.optics↗

arXiv2025

Measuring ultrafast laser pulses using a single-shot amplitude swing implementation

Single-shot characterization techniques are crucial when dealing with shot-to-shot pulse-shape fluctuations (e.g., unstable laser systems, high-power, or with low repetition rate) since the scanning configurations cannot measure single pulses. The demand for simple setups that can be easily adapted to a wide variety of experimental conditions is continuously rising. In this work, we propose a single-shot implementation of amplitude swing, maintaining the compactness, versatility, and robustness of the scanning versions of this technique. First, we theoretically study the proposed implementation, based on a pair of uniaxial wedges. Then, we present the retrieval ptychographic algorithm. Finally, we experimentally demonstrate the setup by comparing the single-shot and scanning traces and their retrieved pulses. In sum, we provide the ultrafast science community with a simple and versatile setup capable of measuring single laser pulses, which is necessary for characterizing fluctuating pulse trains, meeting the current increasing demand.

physics.optics↗

arXiv2025

Ptychographic retrieval for complete ultrashort pulse amplitude swing reconstruction

Ultrafast experiments require precise temporal characterization of laser pulses, where pulse reconstruction is typically achieved through iterative retrieval algorithms. In this context, the amplitude swing technique has emerged as a robust and versatile tool for measuring scalar and vector pulses, using a compact inline setup. Here, we develop a unified theory of amplitude swing and introduce a ptychographic iterative engine algorithm to retrieve scalar and vector pulses from the different amplitude swing implementations (conventional and generalizing). For scalar pulses, we show the new capability of retrieving both amplitude and phase. The algorithm is validated with simulated and experimental traces of scalar and vector pulses, which are benefited from the new algorithm. In conclusion, a powerful tool for pulse characterization is provided, extending the capabilities of amplitude swing (e.g., to double pulses) and enhancing the ultrafast optics measurement toolkit.

physics.optics↗