Broadband terahertz pulse generation driven by an ultrafast thin-disk laser oscillator

Area of Science:

• Optics and Photonics
• Spectroscopy
• Materials Science

Background:

• Terahertz (THz) generation is crucial for advanced spectroscopic applications.
• High-repetition-rate laser systems offer advantages for THz spectroscopy.
• Gallium Phosphide (GaP) is a promising nonlinear crystal for THz generation.

Purpose of the Study:

• To demonstrate broadband THz generation using an ultrafast thin-disk laser (TDL) oscillator.
• To characterize the THz spectroscopic capabilities of GaP crystals.
• To measure the water-vapor absorption spectrum in the THz range with high resolution.

Main Methods:

• Optical rectification of 50-fs pulses from a TDL oscillator at 61 MHz repetition rate.
• Collinear THz generation in crystalline GaP.
• Spectroscopic characterization and THz spectrum analysis.

Main Results:

• Broadband THz radiation generated with a central frequency of ~3.4 THz and spectrum from <1 THz to ~7 THz.
• Spectroscopic characterization of GaP crystal performed.
• Water-vapor absorption spectrum measured with sub-50-GHz resolution over a 5 THz bandwidth.

Conclusions:

• Ultrafast TDL oscillators are suitable for driving MHz-repetition-rate broadband THz systems.
• GaP is effective for generating broadband THz radiation.
• High-resolution THz spectroscopy is achievable with this setup.