Pump-Probe Spectroscopy Using the Hadamard Transform.

Area of Science:

• Spectroscopy
• Physical Chemistry
• Materials Science

Background:

• Conventional pump-probe spectroscopy requires precise temporal separation of excitation and probe pulses.
• Existing methods face limitations with weak probe intensities or noisy detectors, impacting data quality.
• Time resolution is often constrained by mechanical delay lines or fast electronic detection systems.

Purpose of the Study:

• To introduce a new multiplexed pump-probe technique for enhanced data acquisition.
• To demonstrate the feasibility of this method using Hadamard S matrices.
• To address limitations of conventional methods, particularly in challenging experimental conditions.

Main Methods:

• A multiplexing approach measures probe intensity from multiple time points concurrently.
• Hadamard S matrices are employed to encode and decode temporal information.
• Experimental validation was performed on the millisecond timescale, with potential for broader applicability.

Main Results:

• The proposed method successfully transforms multiplexed measurements into a true time-resolved signal.
• Proof-of-concept experiments confirmed the technique's viability.
• The method offers potential signal-to-noise ratio advantages, especially with noisy detectors.

Conclusions:

• This Hadamard S matrix-based pump-probe method offers a powerful alternative to conventional techniques.
• It is particularly advantageous for experiments with weak probe signals or noisy detection.
• The technique shows promise for various timescales, enhancing spectroscopic investigations.