Showing papers by "Eric Tournié published in 2017"

GaSbBi/GaSb quantum well laser diodes

Abstract: We report on the structural and optical properties of GaSbBi single layers and GaSbBi/GaSb quantum well heterostructures grown by molecular beam epitaxy on GaSb substrates Excellent crystal quality and room-temperature photoluminescence are achieved in both cases We demonstrate laser operation from laser diodes with an active zone composed of three GaSb0885Bi0115/GaSb quantum wells These devices exhibit continuous-wave lasing at 25 μm at 80 K, and lasing under pulsed operation at room-temperature near 27 μm

Room-temperature continuous-wave operation in the telecom wavelength range of GaSb-based lasers monolithically grown on Si

Abstract: We report on electrically pumped GaSb-based laser diodes monolithically grown on Si and operating in a continuous wave (cw) in the telecom wavelength range The laser structures were grown by molecular-beam epitaxy on 6°-off (001) substrates The devices were processed in coplanar contact geometry 100 μm × 1 mm laser diodes exhibited a threshold current density of 1 kA/cm−2 measured under pulsed operation at 20 °C CW operation was achieved up to 35 °C with 10 μm × 1 mm diodes The output power at 20 °C was around 3 mW/uncoated facet, and the cw emission wavelength 159 μm, in the C/L-band of telecom systems

Highly doped semiconductor plasmonic nanoantenna arrays for polarization selective broadband surface-enhanced infrared absorption spectroscopy of vanillin

Abstract: Tailored plasmonic nanoantennas are needed for diverse applications, among those sensing. Surfaceenhanced infrared absorption (SEIRA) spectroscopy using adapted nanoantenna substrates is an efficient technique for the selective detection of molecules by their vibrational spectra, even in small quantity. Highly doped semiconductors have been proposed as innovative materials for plasmonics, especially for more flexibility concerning the targeted spectral range. Here, we report on rectangularshaped, highly Si-doped InAsSb nanoantennas sustaining polarization switchable longitudinal and transverse plasmonic resonances in the mid-infrared. For small array periodicities, the highest reflectance intensity is obtained. Large periodicities can be used to combine localized surface plasmon resonances (SPR) with array resonances, as shown in electromagnetic calculations. The nanoantenna arrays can be efficiently used for broadband SEIRA spectroscopy, exploiting the spectral overlap between the large longitudinal or transverse plasmonic resonances and narrow infrared active absorption features of an analyte molecule. We demonstrate an increase of the vibrational line intensity up to a factor of 5.7 of infrared-active absorption features of vanillin in the fingerprint spectral region, yielding enhancement factors of three to four orders of magnitude. Moreover, an optimized readout for SPR sensing is proposed based on slightly overlapping longitudinal and transverse localized SPR.

Low-loss orientation-patterned GaSb waveguides for mid-infrared parametric conversion

Abstract: We design and demonstrate newcomers in the field of frequency down-converters based on quasi-phase matching: low-loss orientation-patterned gallium antimonide ridge waveguides suited to parametric conversion from pumping lasers around 2 µm to mid-infrared wavelengths around 4 µm. Thanks to careful control of the epitaxial growth conditions including low N-type doping and to an optimized dry etching process, losses as low as 0.7 dB/cm at 2 µm and 1.1 dB/cm at 4 µm are obtained.

Surface-enhanced infrared absorption with Si-doped InAsSb/GaSb nano-antennas.

Abstract: We demonstrate surface enhanced infrared absorption spectroscopy using 1-dimensional highly doped semiconductors based on Si-doped InAsSb plasmonic nano-antennas. Engineering the plasmonic array to support the localized surface plasmon resonance aligned with the molecular vibrational absorption mode of interest involves finely setting the doping level and nano-antenna width. Heavily doped nano-antennas require a wider size compared to lightly doped resonators. Increasing the doping level, and consequently the width of the nano-antenna, enhances the vibrational absorption of a ~15 nm thick organic layer up to 2 orders of magnitude compared to the unstructured sample and therefore improves sensing. These results pave the way towards molecule fingerprint sensor manufacturing by tailoring the plasmonic resonators to get a maximum surface enhanced infrared absorption at the target vibrational mode.

Plasmonic bio-sensing based on highly doped semiconductors

Abstract: Highly doped semiconductors, such as Si-doped InAsSb, are promising alternative materials for plasmonic application in the mid-infrared spectral range because they benefit from compatibility with silicon technology, from low losses and from tunable permittivity. We propose to detail what are the main advantages of InAsSb:Si compared to noble metals and how they can be used for bio-sensing applications. We demonstrate that 1-D InAsSb:Si ribbon arrays outperform 1- D gold ribbon arrays because of the latter uses little the lightning rod effect. In the case of 2-D nano-antenna arrays, it is possible to exploit a strong polarization dependent resonance to cover a large spectral range for sensing. Finally, we demonstrate that the highly doped semiconductor 1-D ribbon arrays and 2-D nano-antenna arrays allow surface plasmon resonance (SPR) sensing and surface-enhanced infrared absorption (SEIRA).

Magnetoabsorption of Dirac Fermions in InAs/GaSb/InAs “Three-Layer” Gapless Quantum Wells

Abstract: Cyclotron resonance spectra in high magnetic fields up to 34 T in InAs/GaSb/InAs “three-layer” quantum wells with gapless Dirac fermions have been studied. In quantizing magnetic fields, an absorption line associated with transitions from the lower Landau levels of electrons in a subband with a “conical” dispersion relation has been detected. Experimental energies of the transitions have been compared to theoretical calculations with the eight-band Kane Hamiltonian. The results confirm the gapless band structure of the studied samples.

From 1-dimensional to 2-dimensional periodic semiconductor plasmonic resonators: Designing the optical response for sensing applications

Abstract: Vibrational spectroscopy techniques accomplish the task of detection and identification of molecules. Plasmonic resonator substrates improve these inherently weak techniques: the high electromagnetic field enhancement in proximity of the resonators is exploited to obtain sufficiently strong signals and to decrease the detection limit.