Revealing carrier-envelope phase through frequency mixing and interference in frequency resolved optical gating

Area of Science:

• Ultrafast optics
• Nonlinear spectroscopy
• Terahertz (THz) science

Background:

• Characterizing ultrashort electromagnetic pulses is crucial for understanding nonlinear phenomena.
• Existing methods like electro-optic sampling have limitations in temporal resolution and probe duration.

Purpose of the Study:

• To develop a novel Frequency Resolved Optical Gating (FROG) technique for complete temporal characterization of few-cycle electromagnetic pulses.
• To retrieve the carrier envelope phase (CEP) directly from FROG measurements.
• To enable THz detection beyond the limitations of optical probe duration.

Main Methods:

• Derivation of the Real Domain FROG (ReD-FROG) framework.
• Analysis of interference between sum/difference frequency components and fundamental/frequency components.
• Numerical demonstration of ReD-FROG for self-referenced measurements.
• Proof-of-principle experiment using single-cycle THz pulses.

Main Results:

• Full temporal characterization of few-cycle electromagnetic pulses, including CEP retrieval, is achieved.
• ReD-FROG successfully measures the CEP of single-cycle THz pulses.
• The technique demonstrates THz detection capabilities surpassing electro-optic sampling limitations.

Conclusions:

• ReD-FROG offers a direct and accurate method for temporal characterization and CEP retrieval of ultrashort pulses.
• This advancement significantly enhances THz pulse measurement capabilities.
• The ReD-FROG technique opens new avenues for ultrafast science and technology.