Flexible gratings fabricated in polymeric plate using femtosecond laser irradiation

Flexible gratings embedded in poly-dimethlysiloxane (PDMS) were fabricated using femtosecond laser pulses. Photo-induced gratings in a flexible PDMS plate were directly written by a high-intensity femtosecond (130 fs) Ti: Sapphire laser (λp=800 nm). Refractive index modifications with 4 μm diameters were photo-induced after irradiation of the femtosecond pulses with peak intensities of more than 1×1011 W/cm2. The graded refractive index profile was fabricated to be symmetric around the center of the focal point. The diffraction efficiency of the grating samples is measured by an He–Ne laser. The maximum value of refractive index change (Δn) in the laser-modified regions was estimated to be approximately 3.17×10−3.

► The experimental setup for femtosecond laser-induced refractive index modification in PDMS plate. ► Fabrication of flexible grating embedded gratings in PDMS plate using femtosecond laser irradiation. ► Flexible PDMS plate with embedded diffraction gratings with refractive index modification after femtosecond laser pulse irradiation using white light source.