Fabrication of high-efficiency diffraction gratings in glass

Area of Science:

• Materials Science
• Optics and Photonics
• Nanotechnology

Background:

• Optical gratings are essential components in various photonic devices.
• Efficient fabrication of micro-scale gratings with high refractive index contrast is challenging.
• Ultrafast laser processing offers precise control for microfabrication.

Purpose of the Study:

• To investigate a microfabrication process for optical gratings using ultrafast laser pulses.
• To fabricate gratings with micrometer-scale periods in semiconductor-doped glass.
• To evaluate the diffraction efficiency and angles of the fabricated gratings.

Main Methods:

• Preparation of ZnS- or PbS-doped glass (SiO2-Al2O3-B2O3-CaO-ZnO-Na2O-K2O) via a melting method.
• Microfabrication of transmission diffraction gratings using femtosecond laser pulses.
• Characterization of grating diffraction efficiency and angles at telecommunication wavelengths.

Main Results:

• Successfully fabricated glass transmission diffraction gratings with a high refractive-index difference.
• Achieved approximately 80% first-order diffraction efficiency.
• Observed a first-order diffraction angle of 8 degrees at telecommunication wavelengths.

Conclusions:

• Ultrafast laser pulses enable efficient microfabrication of high-performance optical gratings in semiconductor-doped glass.
• The developed process is suitable for creating gratings for telecommunication applications.
• The high diffraction efficiency demonstrates the potential of this method for photonic integrated circuits.