Time-frequency signal processing of terahertz pulses

Area of Science:

• Terahertz (THz) science and technology
• Signal processing
• Optics and photonics

Background:

• Terahertz (THz) pulse characterization is crucial for understanding THz phenomena.
• Existing methods like frequency-resolved optical gating (FROG) rely on nonlinear optical effects.
• Nonlinear media are typically unavailable or inefficient at THz frequencies.

Purpose of the Study:

• To demonstrate the feasibility of implementing advanced signal processing techniques for THz pulse characterization.
• To provide methods for simultaneous time- and frequency-domain analysis of THz pulses.
• To overcome the limitations of nonlinear methods in the THz regime.

Main Methods:

• Implementation of the fractional Fourier transform (FrFT) at terahertz frequencies.
• Application of spectrogram analysis for terahertz signal processing.
• Utilizing available terahertz devices for signal acquisition and processing.

Main Results:

• Successful implementation of fractional Fourier transform and spectrogram techniques with available THz devices.
• Demonstration that these methods do not require nonlinear media.
• Confirmation of simultaneous time- and frequency-domain characterization capabilities.

Conclusions:

• Fractional Fourier transform and spectrogram are viable techniques for terahertz pulse characterization.
• These methods offer a unique solution for THz pulse analysis in the absence of nonlinear media.
• The demonstrated techniques enable simultaneous time- and frequency-domain analysis of terahertz signals.