Single-Frame Characterization of Ultrafast Pulses with Spatiotemporal Orbital Angular Momentum

Area of Science:

• Optics and Photonics
• Quantum Optics
• Ultrafast Laser Science

Background:

• Spatiotemporal orbital angular momentum (ST-OAM) light enables novel optical vortices and exhibits unique propagation properties.
• Growing interest exists in ST-OAM pulses, but a simple characterization method is lacking.
• Characterizing ultrafast ST-OAM pulses is crucial for their study and application.

Purpose of the Study:

• To develop a simple, stationary, single-frame method for quantitative characterization of ultrafast ST-OAM pulses.
• To enable easy identification of ST-OAM pulse characteristics directly from raw data.
• To facilitate high-throughput feedback for ST-OAM pulse generation and alignment.

Main Methods:

• Spatially resolved spectral interferometry was employed.
• A single-frame, stationary measurement approach was utilized.
• The method allows direct identification of ST-OAM presence and key properties from raw data.

Main Results:

• Demonstrated a simple and straightforward method for ultrafast ST-OAM pulse characterization.
• Successfully identified topological charge numbers and OAM helicity directly from unique data features.
• Enabled full characterization of pulse dispersion and beam divergence after processing.
• The method provides fast feedback for ST-OAM pulse generation and optical alignment.

Conclusions:

• A novel, fast, and simple method for characterizing ultrafast ST-OAM pulses has been established.
• This technique simplifies the analysis of ST-OAM pulses, aiding experimental research.
• The method is extendable to single-shot measurements and supports advancements in structured light applications and metrology.