Time evolution of the second-order nonlinear distribution of poled Infrasil samples during annealing experiments

Area of Science:

• Materials Science
• Nonlinear Optics
• Solid State Physics

Background:

• Thermally poled silica exhibits second-order nonlinear optical properties.
• Understanding the mechanisms of nonlinearity inscription and decay is crucial for device applications.
• Infrasil silica is a common material for optical applications.

Purpose of the Study:

• To investigate the spatial distribution of second-order nonlinearity in thermally poled Infrasil silica.
• To analyze the effects of thermal annealing on the inscribed nonlinearity.
• To elucidate the role of ionic species in the poling and annealing processes.

Main Methods:

• Thermal poling of Infrasil silica samples.
• Thermal annealing experiments.
• Measurement of the spatial distribution of second-order nonlinearity.

Main Results:

• For short poling durations, a single ion recombination model accurately describes the nonlinear distribution.
• For long poling durations, a second positive-charged ion is injected, influencing nonlinearity.
• This second ion acts as a barrier, reducing the mobility of the first ion during annealing and affecting nonlinear erasure.

Conclusions:

• The spatial distribution and stability of induced nonlinearity depend on the ionic species present and their mobility.
• A multi-ion model is necessary to explain the behavior observed in long-duration poling and subsequent annealing.
• Controlling ionic migration during poling and annealing is key to tailoring nonlinear optical properties in silica materials.