Optical Kerr phase shift in a nanostructured nickel-doped zinc oxide thin solid film

Area of Science:

• Materials Science
• Optics
• Nanotechnology

Background:

• The optical Kerr effect is crucial for understanding nonlinear optical properties of materials.
• Nickel-doped zinc oxide thin films are promising for optoelectronic applications.
• Ultrafast optical responses depend on material properties and excitation pulse characteristics.

Purpose of the Study:

• To investigate the optical Kerr effect in nickel-doped zinc oxide thin films.
• To explore the influence of pulse duration (femtosecond vs. picosecond) on nonlinear optical responses.
• To correlate observed optical phenomena with material morphology and underlying physical mechanisms.

Main Methods:

• Thin film samples prepared using ultrasonic spray pyrolysis.
• Z-scan technique employed to measure nonlinear optical properties.
• Femtosecond (80 fs at 825 nm) and picosecond (120 ps at 1064 nm) laser pulses used for excitation.

Main Results:

• Observed opposite signs for the nonlinear refractive index with different pulse durations.
• Self-defocusing and two-photon absorption noted with picosecond pulses.
• Self-focusing and saturated absorption observed with femtosecond pulses.

Conclusions:

• The distinct ultrafast optical responses are attributed to different physical mechanisms.
• Electronic and thermal effects, driven by multiphoton processes, influence energy transfer.
• Nanostructured morphology plays a role in the observed nonlinear optical behavior.