Fabrication of Bragg gratings in subwavelength diameter As2Se3 chalcogenide wires

The inscription of Bragg gratings in chalcogenide (As(2)Se(3)) wires with subwavelength diameter is proposed and demonstrated. A modified transverse holographic method employing He-Ne laser light at a wavelength of λ(w)=633 nm allows the writing of Bragg grating reflectors in the 1550 nm band. The gratings reach an extinction ratio of 40 dB in transmission and a negative photo-induced index change of Δn ∼ 10(-2). The inscription of Bragg gratings in chalcogenide microwires will enable the fabrication of new devices with applications in nonlinear optics and sensing in the near- to mid-IR region of wavelengths.