The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
We report saturable absorption in multilayer epitaxial graphene at 4.7 μm wavelength using mid-infrared quantum cascade laser. From z-scan and differential transmittance measurements, we demonstrate an enhancement of the transmittance of 9 %, attributed to the Pauli blocking effect in the graphene layers. We found that the saturation intensity is in the range of MW/cm2. Our results show the potential...
We present the first direct observation of 26.5 GHz direct modulation of mid infrared buried heterostructure quantum cascade laser (QCL) emitting at 9 μm. For these measurements we have used an ultra-fast QWIP detector with 65 GHz bandwidth. As expected the modulation frequency bandwidth increases by increasing the laser driving DC current. Finally, we demonstrate that the laser cavity round trip...
We present the first room temperature photodection of hundreds on nanowatts using a quantum well mid-infrared detector at 9μm, with a background-limited temperature of 82K and a corresponding background-limited specific detectivity of 1.4×1010 cmHz1/2/W. The photonic architecture consists of an array of double metal nano-antennae and allows to reduce the dark current and increase the absorbed electromagnetic...
Dual-comb sampling of an actively mode-locked phase-stabilized THz quantum cascade laser with 10 GHz Ti:sapphire frequency combs provides a method to directly determine the absolute frequency of the QCL with Hz-level precision.
Enhanced electroluminescence in arrays of double metal patch microcavities is demonstrated. The enhancement originates from high Purcell factors and efficient photon out-coupling as the period of the array is increased.
Plasmonic THz photodetectors have been realized in this work, by implementing the active region of a 5 THz quantum well detector with an antenna-coupled microcavity array. Our results demonstrate a clear improvement in responsivity, polarization insensitivity and background limited performance.
We report our recent work on integrated AlGaAs sources of bi-photon states operating at room temperature and telecom wavelength. The extreme versatility of the emitted state and the electrical injection make these devices very good candidates for future photon communications.
Optical sidebands are generated by difference frequency mixing between a resonant bandgap near-infrared beam and a terahertz (THz) wave. This is realized within the cavity of a THz quantum cascade laser using resonantly enhanced non-linearities. Multiple order optical sidebands and conversion efficiencies up to 0.1% are shown.
We report on the modeling and optical characterization of AlGaAs/InAs quantum-dot microring diode lasers designed for terahertz (THz) difference frequency generation (DFG) between two whispering gallery modes (WGMs) around 1.3 m. In order to investigate the spectral features of this active device in the two frequency ranges, we performed different measurements on ad hoc passive samples. For the...
We present a mid-infrared quantum cascade laser embedded into a micro-strip line for high frequency modulation. Modulating with less than 10mW at the round trip frequency, we observe beat-note injection locking within a range in the order of 1 MHz.
Difference frequency mixing between a resonant bandgap near-infrared beam and a THz wave is demonstrated within the cavity of a quantum cascade laser using a resonantly enhanced second order non-linearity. Conversion efficiencies up to 0.13% are shown that are comparable to those shown by Free Electron Laser measurements.
Phase-matched difference frequency mixing between a resonant bandgap near-infrared beam and a THz wave is demonstrated within a quantum cascade laser using second order non-linearities. Conversion efficiencies up to 0.16% are shown.
We demonstrate semiconductor resonators operating on the fundamental monopolar resonance which corresponds to the fundamental oscillation mode of split-ring resonators. Their size is considerably below the optical diffraction limit in all three dimensions of space. The maximum confinement is obtained for resonators operating at a wavelength of λ ∼ 272 μm (v ∼ 1.1 THz): they have a diameter of 13 μm...
A new scheme for coherent detection of a laser electric field has been demonstrated by stabilizing the emission frequency of a THz quantum cascade laser (QCL) on a harmonic of the repetition rate of a fs-fiber laser. This scheme has permitted to measure the pulses (10ps long) of a QCL that operates mode-locking, while the injected current is modulated close to its round trip frequency.
Ultrafast gain switching of THz quantum cascade lasers is demonstrated and applied to amplify sub-ps THz pulses as well as to initiate THz laser emission with a controlled phase. Impact on THz time domain spectroscopy and on future development for mode-locking will be discussed.
Laser action normally is initiated by the amplification of spontaneous emission. As spontaneous emission is a random process, the carrier phase of a laser is different each time a laser is turned on. As a consequence, it is not possible to measure the time-resolved field of a free-running laser using coherent detection techniques [1, 2]. Here we show [3] that it is possible to fix the carrier phase...
Mode-locked femtosecond (fs) lasers have become established as a means to probe fast transient phenomena, with pump-probe experiments using two mode-locked fs-lasers with slightly different repetition rates becoming widespread [1,2]. In these experiments, the time delay between the pump and the probe laser pulses is automatically scanned at the difference frequency between the repetition rates. Such...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.