Asymmetric double-pulse interferometric FROG for visible-wavelength time-domain spectroscopy

Area of Science:

• Optics and Photonics
• Spectroscopy
• Materials Science

Background:

• Standard frequency-resolved optical gating (FROG) methods face limitations in extending time-domain spectroscopy to visible frequencies.
• Accurate measurement of complex dielectric functions at visible wavelengths requires preserving both zero- and first-order phase information.
• Existing techniques struggle to provide the necessary temporal resolution and phase sensitivity for ultrafast spectroscopic studies in this range.

Purpose of the Study:

• To propose and validate a novel interferometry-type FROG technique for time-domain spectroscopy in the visible frequency range.
• To enable phase-sensitive spectroscopic studies by preserving critical phase information (φ₀, φ₁) typically lost in standard FROG.
• To develop an ultrafast-compatible and ambiguity-free method for complex dielectric function measurement at visible wavelengths.

Main Methods:

• Development of an interferometry-type frequency-resolved optical gating (FROG) system.
• Implementation of a double-pulse scheme to activate a unique phase-locking mechanism.
• Numerical simulations to verify the preservation of zero- and first-order phases (φ₀, φ₁).
• Time-domain signal reconstruction and analysis protocol for data interpretation.

Main Results:

• The proposed double-pulse scheme successfully activates a phase-locking mechanism, preserving both zero- and first-order phases.
• This mechanism overcomes the limitations of standard FROG, making previously inaccessible phase information available.
• Numerical simulations confirm the feasibility of achieving sub-cycle temporal resolution for time-domain spectroscopy.

Conclusions:

• The interferometry-type FROG method effectively extends time-domain spectroscopy into challenging visible frequencies.
• The technique provides an ultrafast-compatible and ambiguity-free approach for complex dielectric function measurement.
• This advancement enables precise phase-sensitive spectroscopic studies at visible wavelengths with sub-cycle temporal resolution.