Ultra-rapid electro-optic sampling of octave-spanning mid-infrared waveforms

Area of Science:

• Optics and Photonics
• Spectroscopy
• Physical Chemistry

Background:

• Mid-infrared (MIR) spectroscopy is crucial for molecular analysis.
• Traditional methods for MIR pulse characterization are often slow.
• Ultra-fast laser technologies require advanced diagnostic tools.

Purpose of the Study:

• To demonstrate an ultra-rapid electro-optic sampling (EOS) technique for MIR pulses.
• To achieve high-resolution waveform acquisition within a short timeframe.
• To enable new applications in molecular dynamics and chemical analysis.

Main Methods:

• Utilized a mechanically scanning mirror driven by a sonotrode at 19 kHz for delay scanning.
• Implemented forward and backward acquisition at 38 kHz for enhanced speed.
• Employed interferometric tracking and a predictor-corrector algorithm for precise delay-axis determination.

Main Results:

• Successfully performed ultra-rapid EOS of octave-spanning MIR pulses (9 μm).
• Achieved a spectral intensity dynamic range of 1.6 × 10^5 within a 1.6-ps delay range.
• Acquired waveforms in just 26 μs with attosecond precision for delay determination.

Conclusions:

• The developed ultra-rapid EOS technique significantly reduces measurement time for MIR pulses.
• This method is compatible with broad optical bandwidths, short pulse durations, and high average powers.
• Potential applications include molecular fingerprinting, tracking biological and chemical processes, and infrared-spectroscopic flow cytometry.