Terahertz wave generation via difference frequency generation using 2D In_xGa_1-xSe crystal grown from indium flux

Area of Science:

• Solid State Physics
• Materials Science
• Optoelectronics

Background:

• Terahertz (THz) wave generation is crucial for various scientific and technological applications.
• Gallium selenide (GaSe) is a known material for nonlinear optical frequency conversion, but its efficiency can be limited.
• Developing new materials with enhanced nonlinear optical properties is essential for improving THz generation.

Purpose of the Study:

• To demonstrate THz wave generation using a mixed indium gallium selenide (InxGa1-xSe) crystal.
• To investigate the structural properties and indium incorporation in the InxGa1-xSe crystal.
• To evaluate the performance of InxGa1-xSe for THz wave generation compared to undoped GaSe.

Main Methods:

• Growing InxGa1-xSe mixed crystals from indium flux.
• Characterizing the crystal structure and composition using X-ray diffraction (XRD) and electron probe microanalysis (EPMA).
• Measuring the generated THz wave power and conversion efficiency using difference frequency generation (DFG).

Main Results:

• Successfully generated THz waves at a frequency of 9.7 THz using the InxGa1-xSe crystal.
• Confirmed indium substitution at gallium sites in the InxGa1-xSe crystal through XRD and EPMA, consistent with Vegard's law.
• Achieved a maximum THz wave power of 39 pJ.
• Obtained a conversion efficiency of 1.7×10^-5 J^-1, which is 28 times greater than that of undoped GaSe.

Conclusions:

• InxGa1-xSe is a promising material for efficient THz wave generation.
• Indium incorporation significantly enhances the nonlinear optical properties for THz production.
• The developed material offers a substantial improvement over conventional GaSe for DFG-based THz sources.