GaSb Laser Research Articles

镀膜对2.0 μm锑化物激光器性能的提升

镀膜对2.0 μm锑化物激光器性能的提升

Lightweight mid-infrared methane sensor for unmanned aerial systems

The design and field performance of a compact diode laser-based instrument for measuring methane on unmanned aerial systems (UAS) is described. The system is based on open-path, wavelength modulation spectroscopy with a 3.27 µm GaSb laser. We design two versions of the sensor for a long-endurance fixed wing UAS and a rotary wing hexacopter, with instrument masses of 4.6 and 1.6 kg, respectively. The long-endurance platform was used to measure vertical profiles of methane up to 600 m in altitude and showed repeatability of 13 ppbv between multiple profiles. Additionally, the hexacopter system was used to evaluate the evolution of methane in the nocturnal boundary layer during the ScaleX field campaign in Germany, where measured data is consistent with supporting ground-based methane and meteorological measurements. Testing results on both platforms demonstrated our lightweight methane sensor had an in-flight precision of 5–10 ppbv Hz−1/2.

Design and Analysis of 2-μm InGaSb/GaSb Quantum Well Lasers Integrated Onto Silicon-on-Insulator (SOI) Waveguide Circuits Through an Al2O3 Bonding Layer

GaSb-based quantum well (QW) laser diode, with emission wavelength ∼2 μm, integrated onto a silicon-on-insulator (SOI) waveguide circuit through a high-thermal-conductivity Al2O3 bonding layer has been designed and analyzed. Prior to bonding, the fabricated Fabry–Perot GaSb QW laser worked under continuous wave operation at room temperature, with a low threshold current of 37 mA at the emission wavelength of 2019 nm, demonstrating high material quality. A tapered structure has been used for evanescent coupling of light from the GaSb laser to the underlying Si waveguide. Instead of using SiO2 for direct bonding or Benzocyclobutene for adhesive bonding, the use of Al2O3 to directly bond GaSb lasers onto SOI wafers is proposed. The optical mode distribution simulations by a beam propagation method software show that light can be coupled efficiently to the underlying Si waveguide through the tapered structure without compromise in optical coupling efficiency. Furthermore, there is a significant reduction (∼70%) in the total thermal resistance compared with the same structure using a SiO2 bonding layer. Our results suggest that the Al2O 3 bonding layer could be a promising candidate for III–V lasers integrated on SOI circuits, where thermal dissipation is very critical.

Publisher’s Note: “Two-layer photo-thermal deflection model to study the non-radiative recombination process: Application to Ga0.7In0.3As0.23Sb0.77/GaSb and Al0.3Ga0.7As0.08Sb0.92/GaSb laser structures” [J. Appl. Phys. 113, 183705 (2013)

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InAs–GaSb laser: Prospects for efficient terahertz emission

We suggest to use InAs/GaSb coupled quantum wells for terahertz lasing. In these heterostructures terahertz lasing is based not on intersubband but on interband transitions. Crucial advantages of this design in comparison with intersubband lasers are (i) a large value of the interband dipole matrix element and (ii) easier maintenance of population inversion. These advantages lead to a gain of two orders of magnitude higher than that for intersubband lasing. Even higher gain can be obtained in special design InAs/GaSb W-structures where a hybridization gap of 1–3 THz is formed and optical density of states is singular.

Toward making layered films using selective ionization in InSb and GaSb laser ablation plumes

The 308 nm laser ablation of InSb and GaSb has been investigated with the goal being to exert macroscopic control over the ablation plume. By taking advantage of the lower ionization potential of the group III element, In or Ga can be selectively ionized within the ablation plume by a 193 nm (6.4 eV) photon. The ionized species are removed from the plume with an electric field. As shown by x-ray photoelectron spectra, films subsequently deposited are diminished in In or Ga. A three-cycle deposition study demonstrates that a depleted layer of InSb can be deposited between two nondepleted layers of InSb.

1.5 μm Ga(Al)Sb laser grown on GaAs substrate by MBE

Ga(Al)Sb-based laser diodes grown by molecular beam epitaxy on GaAs substrates are presented. The properties of ridge waveguide lasers based on this structure are discussed. The lasers show lasing activity up to 273 K with a laser threshold current density of 6.58 kA/cm 2 at 77 K.

Determination of the optical and thermal properties of semiconductors with the photothermal method

The photothermal method has been used for the determination of several thermal and optical material properties. We demonstrate the use of the photothermal method for the investigation of thermal and optical properties of the GaAlAsSb and GaInAsSb layers which are, respectively, the confinement layer and the active layer of the GaAlAsSb/GaInAsSb/GaAlAsSb/GaSb laser heterostructure. These layers were deposited on a GaSb substrate in its liquid phase by means of epitaxy.

Fine structure of the spectra of GaSb laser diodes

Fine structure of the spectra of GaSb laser diodes