(INVITED) Methods for determining the refractive indices and thermo-optic coefficients of chalcogenide glasses at MIR wavelengths

Chalcogenide glasses have attracted much attention for the realization of photonic components owing to their outstanding optical properties in the mid-infrared (MIR) region. However, relatively few refractive index dispersion data are presently available for these glasses at MIR wavelengths. This paper presents a mini review of methods we have both used and developed to determine the refractive indices and thermo-optic coefficients of chalcogenide glasses at MIR wavelengths, and is supported by new results. The mini review should be useful to both new and established researchers in the chalcogenide glass field and fields of MIR optics, fiber-optics and waveguides. Three groups of methods are distinguished: (1) spectroscopic ellipsometry, (2) prism-based methods, and (3) methods using Fourier transform infrared (FTIR) transmission data. The mini review is supported by a brief discussion of refractive index models

Fiber Bragg gratings inscribed using 800nm femtosecond laser and a phase mask in singleand multi-core mid-IR glass fibers

For the first time, Fiber Bragg grating (FBG) structures have been inscribed in single-core passive germanate and three-core passive and active tellurite glass fibers using 800 nm femtosecond (fs) laser and phase mask technique. With fs peak power intensity in the order of 10(11)W/cm(2), the FBG spectra with 2nd and 3rd order resonances at 1540 and 1033 nm in the germanate glass fiber and 2nd order resonances at approximately 1694 and approximately 1677 nm with strengths up to 14 dB in all three cores in the tellurite fiber were observed. Thermal responsivities of the FBGs made in these mid-IR glass fibers were characterized, showing average temperature responsivity approximately 20 pm/ degrees C. Strain responsivities of the FBGs in germanate glass fiber were measured to be 1.219 pm/microepsilon

3D photonics in the mid-infrared : parametric study of ultrafast laser inscribed waveguides for stellar interferometry

We present a study on glass materials that are potentially suitable for the fabrication of low-loss waveguides in the mid-infrared, more specifically in the region 3 - 5 μm. The midinfrared is especially interesting for applications such as molecular fingerprinting and interferometry for Earth-like exoplanet hunting. We study the optical properties of different glasses and use the femtosecond laser direct-write technique to inscribe waveguides inside them. We characterized the single-mode transmission properties of the waveguides, mode confinement and induced refractive index change as well as determined the waveguide propagation losses.2 page(s

Visualization 1: Periodically patterned germanium surfaces modified to form superhydrophobic, IR-transmissive substrates

Video showing water droplets on the surface of GeHC before PFOTS modification. Originally published in Optical Materials Express on 01 October 2016 (ome-6-10-3254

Mid-infrared astrophotonics: Study of ultrafast laser induced index change in compatible materials

International audienceThe mid-infrared wavelength regime 3:5 - 4:1μm, known as the astronomical L' band is of special interest for exoplanet hunting. Mid-IR compatible photonic technologies are an enabling platform for a range of critical observational science using compact instruments on the next generation of Extremely Large Telescopes. Pupil remapping interferometry is a technique in which subapertures of the telescope pupil (2D) are reformatted into a 1D linear array. This can be done efficiently using 3D photonics. One of the most important techniques to fabricate 3D photonic devices in glass is ultrafast laser inscription. However, common silicate glasses are opaque above 2-2.2 μm and therefore not useful for the fabrication of waveguides at mid-infrared wavelengths. Here we present a study of mid-infrared transparent materials that are compatible with the ultrafast laser inscription technique. This study will inform the development of mid-infrared photonic devices for future exoplanetary discovery. © 2017 Optical Society of America

Visualization 2: Periodically patterned germanium surfaces modified to form superhydrophobic, IR-transmissive substrates

Video showing water droplets on the surface of GeHC after PFOTS modification. Originally published in Optical Materials Express on 01 October 2016 (ome-6-10-3254