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We present electroluminescence from ZnCdSe/ZnCdMgSe Quantum Cascade structures, with 3 times higher luminescence efficiency, 30% narrower electroluminescence linewidths than our first demonstration. The measured turn-on voltage matches with the calculated value.
A semiconductor laser with active layer consisting of a patterned quantum dot lattice demonstrates evidence of miniband formation resulting from inter-dot coupling. Excited state lasing is thought to result from a phonon bottleneck-like effect.
Terahertz pulse generation is demonstrated by a resonant femtosecond interband excitation of the miniband of a quantum-cascade-laser. The laser gain is subsequently used to amplify the terahertz pulse generated as it propagates through the cavity.
Reduced threshold currents and high temperature operation in surface emitting quantum cascade lasers are demonstrated by using ring-based cavities. The devices exhibit robust and tunable single-mode operation as well as low divergence symmetric beams.
We demonstrate transmission spectroscopy between a monostatic transceiver based on a wavelength-beam-combined quantum-cascade-laser array and a retroreflector placed at 35 meters.
We present an experimental demonstration for an elastic-backscattering LIDAR system measurement using a Quantum Cascade laser (QCL). The laser emits a peak power of above 13W at 80K and with a wavelength of 4.5µm.
We develop a ground-based, non-cryogenic, open-path quantum cascade laser ammonia sensor operating at 9.06μm for high sensitivity atmospheric measurements. A cylindrical mirror multi-pass optical cell and wavelength modulation spectroscopy allow for pptv detection limits.
A 3.1THz phonon depopulation-based quantum-cascade-laser is investigated using terahertz time domain spectroscopy. A gain of 25cm−1 and absorption features due to the lower laser level being populated from a parasitic electronic channel are highlighted.
We experimentally investigate the effects of cascade third-order and fifth-order nonlinear optical processes in a four-level atomic system. The relative strengths of these high-order nonlinear optical processes can be manipulated by controlling the atomic coherence.
A terahertz quantum cascade laser and an integrated Auston-switch are coupled to perform ultrafast gain switching. The resulting non-equilibrium gain is not clamped above laser threshold and large amplification of input terahertz pulses is demonstrated.
We report a novel tuning mechanism based on a “wire-laser” with subwavelength transverse dimensions(w≪λ). By manipulating the waveguided mode propagating outside the cavity, frequency tuning of ∼137GHz (3.6%) is demonstrated from a single-laser device at ∼3.8THz.
We present a novel method for the light-induced tuning of a grating-free mid-IR QCL utilizing the absorbance changes of a photochromic cladding. This photosensitization allowed for reversible shifts in the emission wavelength of 5 cm−1.
The complex interplay by tunneling and scattering in quantum cascade lasers is analyzed with nonequilibrium Green's functions. Data for a recently proposed simple structure based on only two wells per period is presented. This simple structure allows to visualize the relevance of the tunneling resonance very clearly. It is argued that a QCL design needs at least three levels per period, thus further...
We present a microcavity for the Terahertz based on a lumped circuit inductor-capacitor (LC) resonator. The substitution of the capacitor dielectric by a gain medium allows the demonstration of a Terahertz laser with a strongly sub-wavelength electronic resonator. Lasing is observed at 1.5 THz at 4.2 K. The LC resonator allows fabricating microcavities with dimensions arbitrarily smaller than the...
We report novel quantum cascade laser sources based on difference-frequency generation in nonlinear sections localized near exit facets. This new approach allows for infrared-to-terahertz conversion efficiencies above 1mW/W2. Experimentally, devices operating at 4THz are discussed.
The maximum operating temperature of previously reported terahertz quantum-cascade lasers (QCLs) has empirically been limited to a value of ~ ħω/kB. Here, we report a new design scheme for terahertz QCLs and achieve 163-K operation for a 1.8-THz QCL, which is a factor of 1.9 larger than ħω/kB.
We demonstrate single mode operation of Quantum Cascade lasers employing a folded Fabry-Perot resonator waveguide design. Single mode emission is achieved with ∼20dB side mode suppression up to ∼400mA above threshold current in pulsed operation.
A thermoelectric effect is observed in quantum cascade lasers and validated through thermal/electrical transport modeling. Choosing the proper polarity leads to an active core heat reduction of 9 K for a 7.5 kW/cm2 thermal load.
PPMgSLT is used for mode-locking of a diode-pumped Nd:GdVO4 laser by intracavity SHG. Stable and self-starting operation is observed achieving output powers of up to 4.7 W and pulse durations as short as 3.2 ps.
We demonstrated 105 W pico-second output from a cascaded Nd:YVO4 amplifier laser system consisting of a Nd:YVO4 bounce amplifier with a photorefractive phase-conjugate mirror and a second diode-side-pumped Nd:YVO4 bounce power amplifier.
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