Correlating structure with non-linear optical properties in xAs40Se60·(1-x)As40S60 glasses

Area of Science:

• Materials Science
• Solid State Chemistry
• Optoelectronics

Background:

• Chalcogenide glasses, specifically those based on arsenic sulfides and selenides, are crucial for optical applications due to their unique properties.
• Understanding the atomic structure and its relationship with optical characteristics is key to developing new materials.

Purpose of the Study:

• To investigate the structural properties and non-linear optical behavior of As40Se60·(100 - x)As40S60 glasses.
• To explore the correlation between chalcogen atom distribution and non-linear refractive index (n2).

Main Methods:

• Neutron and X-ray total scattering for structural analysis.
• Raman spectroscopy and 77Se Magic Angle Spinning Nuclear Magnetic Resonance (MAS-NMR) for detailed structural insights.
• Measurement of non-linear refractive indices (n2) and densities.

Main Results:

• No evidence of homopolar bonds was found in the studied glasses.
• Neutron correlation functions indicated a non-random distribution of sulfur and selenium atoms in sulfur-rich compositions.
• The average number of sulfur atoms near selenium atoms (nSeS) and the non-linear refractive index (n2) showed non-linear variations with composition for <50 mol% As40Se60.
• A direct linear correlation was observed between n2 and nSeS.

Conclusions:

• The non-linear refractive index (n2) of these chalcogenide glasses is strongly influenced by the specific arrangement of sulfur and selenium atoms.
• The findings suggest that n2 can serve as an indicator of chalcogen distribution, providing a pathway for tailoring optical properties.