Chalcogenide waveguides on a sapphire substrate for mid-IR applications.

We report on the fabrication of arsenic tri-sulfide chalcogenide strip waveguides on a sapphire substrate, suitable for guiding 0.55-5 µm wavelengths. Propagation losses measured using the Fabry-Perot resonator technique are 2.78 dB/cm. The chalcogenide layer refractive index dispersion is evaluated by measuring the transmission as a function of wavelength prior to waveguide fabrication. Numerical simulations are used to compare between silica and sapphire substrates for mid-IR transmittance and to calculate the waveguide's effective refractive index in a suggested design. The use of a low-loss sapphire substrate redefines the mid-IR boundaries of chalcogenide waveguides for linear and nonlinear applications.

Liquid crystal high-resolution optically addressed spatial light modulator using a nanodimensional chalcogenide photosensor.

The fabrication and performance of an optically addressed spatial light modulator (OASLM) based on nematic liquid crystal and nanodimensional amorphous arsenic trisulfide (a-As2S3) chalcogenide glassy films are described. The photoconductive a-As2S3 layers are used both as photoalignment material and as a photosensor. The use of the OASLM as a color converter is demonstrated in the transmission mode. The phase retardation dynamic range is over 3π. Diffraction efficiency measurements show a high resolution (150 lp/mm at 50% MTF). A wide variety of materials from the chalcogenide glass (ChG) family are useful for simple fabrication of high-resolution OASLMs depending on the desired wavelength.

Stimulated Brillouin scattering amplification in centimeter-long directly written chalcogenide waveguides.

Stimulated Brillouin scattering (SBS) amplification is obtained in directly written As2S3 channel waveguides. Centimeter-long waveguides were written using a Ti:sapphire femtosecond laser, operating at a central wavelength of 810 nm. The cross-section of the waveguides was of 4 µm×1 µm. A Brillouin frequency shift of 7.5 GHz is observed, in general agreement with corresponding previous studies. The SBS gain spectrum in the short waveguides is comparatively broad, with a full width at half-maximum of 200 MHz. We attribute the broad linewidth to the spatial evolution of the electromagnetic field profile along the waveguide.