Measurement of non-linear optical properties in graphene oxide using the Z-scan technique.

Area of Science:

• Materials Science
• Non-linear Optics
• Nanomaterials

Background:

• Graphene oxide (GO) is a promising nanomaterial with unique optical properties.
• Understanding its non-linear optical (NLO) behavior is crucial for applications in photonics and optoelectronics.
• Previous studies have explored GO's NLO properties, but systematic investigations across varying concentrations and laser powers are needed.

Purpose of the Study:

• To determine the non-linear optical parameters of graphene oxide (GO) dispersions.
• To investigate the influence of excitation laser power on these parameters.
• To provide quantitative data for the non-linear refractive index (η₂), non-linear absorption coefficient (β), and third-order susceptibility (χ⁽³⁾) of GO.

Main Methods:

• Utilized the Z-scan technique to measure the non-linear optical response of GO samples.
• Employed a continuous-wave (CW) Nd:YAG laser emitting at 532 nm for excitation.
• Measured normalized transmittance to derive NLO parameters at various GO concentrations and laser powers.

Main Results:

• Successfully determined the non-linear refractive index (η₂), non-linear absorption coefficient (β), and third-order susceptibility (χ⁽³⁾) for GO dispersions.
• Observed a significant increase in η₂, β, and χ⁽³⁾ with rising excitation laser power.
• Reported a high order of magnitude for the non-linear absorption coefficient (β) around ~10⁻² cm/W.

Conclusions:

• Graphene oxide exhibits significant non-linear optical properties that are dependent on laser power.
• The quantitative data obtained provides valuable insights for designing GO-based photonic devices.
• Further research can explore GO's NLO behavior in different environments and at various wavelengths.