A double guidance mechanism, nitroaniline based microstructured optical fiber.

Area of Science:

• Materials Science
• Optics and Photonics
• Nonlinear Optics

Background:

• Microstructured optical fibers offer unique light guidance properties.
• Photonic bandgap (PBG) fibers utilize periodic structures for light confinement.
• Second harmonic generation (SHG) is a key nonlinear optical process for frequency conversion.

Purpose of the Study:

• To develop and characterize a novel all-solid composite optical fiber.
• To investigate wavelength-dependent light guidance mechanisms.
• To explore the second harmonic generation capabilities of the composite fiber.

Main Methods:

• Fabrication of a silica glass microstructured optical fiber infiltrated with 2-methyl 4-nitroaniline.
• Optical characterization across a broad wavelength range.
• Post-processing via annealing to tune nitroaniline morphology.
• Second harmonic generation measurements using 1064 nm laser excitation.

Main Results:

• Demonstration of a transition from photonic bandgap guidance to modified total internal reflection guidance with increasing wavelength.
• Attribution of the guidance transition to the dispersion of low Abbe number nitroaniline.
• Enhancement of transmission bandgap extinction ratios through annealing.
• Observation of second harmonic generation with conversion efficiency dependent on nitroaniline packing.

Conclusions:

• The composite optical fiber exhibits tunable guidance and nonlinear optical properties.
• Potential applications include all-optical gates and light conversion devices.
• The interplay between guidance regimes and nonlinear effects offers unique device possibilities.