Enhancing Quartz Infrared Absorption by Tuning Femtosecond Laser Surface Texturing Patterns

Area of Science:

• Materials Science
• Optoelectronics
• Laser Physics

Background:

• Quartz possesses excellent properties for optoelectronic and sensing applications.
• Its transparency above 5 μm hinders its use in near- and mid-infrared photodetection.
• Laser surface texturing offers a method to create 'black quartz' and overcome transparency limitations.

Purpose of the Study:

• To investigate femtosecond (fs) laser surface texturing strategies on quartz.
• To enhance quartz's light absorption for infrared photodetection.
• To develop a maskless and chemical-free surface functionalization method.

Main Methods:

• Uniform milling, grid-patterned grooves, and localized crater arrays were created using fs laser texturing on a 1 mm thick α-quartz wafer.
• Transmittance was measured across the infrared spectrum to evaluate blackening performance.
• Surface morphology was analyzed to understand light absorption mechanisms.

Main Results:

• Fs-laser-treated quartz exhibited a transmittance reduction of up to 60% in the infrared range.
• Crater matrices demonstrated the most effective blackening.
• Enhanced absorption was linked to light-trapping effects from tapered crater geometry and increased optical confinement.

Conclusions:

• Fs laser texturing is a viable strategy for fabricating black quartz substrates.
• Crater arrays provide superior light absorption for broadband infrared photodetection.
• This maskless, chemical-free method enables advanced quartz-based sensing applications.