High-power, tunable difference frequency generation source for absorption spectroscopy based on a ridge waveguide...

Area of Science:

• Photonics and Optical Engineering
• Mid-Infrared Spectroscopy
• Nonlinear Optics

Background:

• Difference frequency generation (DFG) is crucial for accessing the mid-infrared (mid-IR) spectrum.
• Developing efficient and compact mid-IR sources is essential for various applications, including gas sensing.
• Waveguide-based DFG offers advantages in terms of power and efficiency.

Purpose of the Study:

• To characterize a novel waveguide designed for DFG in the mid-IR at 3.52 µm.
• To evaluate the performance metrics of the waveguide, including output power and conversion efficiency.
• To demonstrate the potential of the generated mid-IR light for trace gas sensing.

Main Methods:

• Fabrication and characterization of a novel optical waveguide.
• Measurement of mid-IR output power using a power meter.
• Determination of external conversion efficiency.
• Beam quality assessment using the second moment method to determine the optical beam propagation factor (M²).
• Demonstration of trace gas sensing using 2-f absorption spectroscopy.

Main Results:

• The novel waveguide achieved a high mid-IR output power of 15 mW.
• An external conversion efficiency of up to 19 %W⁻¹ was obtained.
• The optical beam propagation factor M² was measured to be 1.18, indicating good beam quality.
• Successful demonstration of trace gas sensing using the generated mid-IR light.

Conclusions:

• The characterized waveguide is a highly efficient source for mid-IR DFG at 3.52 µm.
• The high power and excellent beam quality make it suitable for demanding applications.
• The demonstrated trace gas sensing capability highlights its potential for high-precision environmental and industrial monitoring.