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Harvard College

Ecole Polytechnique Federale De Lausanne

Jérôme Faist

Alfredo Bismuto

Yves Bidaux

Richard Maulini

Andreas Hugi

Antoine Muller

Mattias Beck

Marko Lončar

Antoine Müller

Stephane Blaser

Maria Amanti

Markus Geiser

Filippos Kapsalidis

Gustavo Filipe Ferreira Villares

Yazan Lampert Almahmoud

Alexa Herter

Alessandro Tomasino

Amirhassan Shams-ansari

Johanna Wolf

Emilio Gini

Antoine Mueller

Ileana-Cristina Benea-chelmus

Christoph Walther

Borislav Hinkov

Giacomo Scalari

Stéphane Blaser

A terahertz device for detecting or emitting or for both detecting and emitting electromagnetic waves in the terahertz frequency range. The terahertz device comprises: a first waveguide branch and a second waveguide branch, the first and second waveguide branches being configured to allow optical signals to propagate through them, the first and second waveguide branches being nonlinear dielectric elements with a thickness of at most 500 micrometres; and an antenna arrangement comprising a set of antennas for capturing and/or emitting electromagnetic waves in the terahertz frequency range, the antennas being placed along at least one of the waveguide branches in an immediate vicinity of the respective waveguide branch and/or around the respective waveguide branch to at least partially enclose the respective waveguide branch in a respective antenna gap of the respective antenna.

On-chip terahertz thin-film devices

A waveguide heterostructure for a semiconductor laser with an active part, comprising an active region layer depending of the type of semiconductor used, which is sandwiched between an electrode layer and a substrate, usable for dispersion compensation in a semiconductor laser frequency comb setup, an optical frequency comb setup and a manufacturing method.

Waveguide heterostructure for dispersion compensation in semiconductor laser

Semiconductor Quantum Cascade Lasers (QCLs), in particular mid-IR lasers emitting at wavelengths of about 3-50 &#x3bc;m, are often designed as deep etched buried heterostructure QCLs. The buried heterostructure configuration is favored since the high thermal conductivity of the burying layers, usually of InP, and the low losses guarantee devices high power and high performance. However, if such QCLs are designed for and operated at short wavelengths, a severe disadvantage shows up: the high electric field necessary for such operation drives the operating current partly inside the insulating burying layer. This reduces the current injected into the active region and produces thermal losses, thus degrading performance of the QCL. The invention solves this problem by providing, within the burying layers, effectively designed current blocking or quantum barriers of, e.g. AIAs, InAIAs, InGaAs, InGaAsP, or InGaSb, sandwiched between the usual InP or other burying layers, intrinsic or Fe-doped. These quantum barriers reduce the described negative effect greatly and controllably, resulting in a QCL operating effectively also at short wavelengths and/or in high electric fields.

Quantum cascade laser with current blocking layers

A method for optical and electrical signal processing of a multi-heterodyne signal generated by a multi-mode semi-conductor laser, for a system comprising two laser sources and an sample interaction unit. At least the beam of one of the laser passes through said sample interaction unit before being combined on a detector. The first laser is tuned () by an amount keeping the tuning result within the available detector bandwidth (). Then the second laser is roughly tuned by the same amount as the tuning of the first laser to bring back the signal to the vicinity () of the original place in the RF-domain and within the bandwidth () of the detector. The tuning steps are repeated with different value of mode spacing for reconstructing the sample spectrum and provide a high resolution image of the dip () absorption line ().

Method for optical and electrical signal processing of a multi-heterodyne signal generated by a multi-mode semi-conductor laser and detection device utilizing that method

Semiconductor lasers, in particular Quantum Cascade Lasers (QCLs) are tuable especially in the mid-IR spectral range, e.g. in wavelengths of about 3-14 &#x3bc;m, by precisely controlling the laser's temperature in the vicinity of the active region. The present invention introduces a novel design for locally heating the active region, thereby allowing fast heating and thus tuning a laser. It is generally applicable for lasers across the field, e.g. to QCLs with multi-color emitters or to Vertical-Cavity Single-Emitter Lasers (VCSELs) or to Distributed Feedback (DFB) lasers. Essentially, the invention consists of structurally integrating a heating resistor as part of the laser, placed close to the component to be temperature-controlled, i.e. the active region or the grating, etc., and feeding this resistor with a variable electrical current in order to locally control the thermal dissipation. In multi-emitter lasers, a resistor can be associated with each emitter section to tune the temperature of each section and thus its emitted wavelength. Similarly, in multisection DBR lasers, with a resistor associated with each grating, the latter can be tuned and thus the associated wavelength of the optical cavity. The invention also includes a novel manufacturing process, especially for buried heterostructure lasers.

Tunable laser, a method for making, and a method for operating such a laser

A microwave circuit includes at least one inductive portion and at least one capacitive portion and having a resonance frequency, the microwave circuit including a material which acts as a dielectric for the capacitive portion, characterized in that the material acting as a dielectric includes an active region that is an electrically pumped semiconductor heterostructure having at least two energy levels whose energy separation is close to the resonance frequency of the microwave circuit.

Microwave circuit

A quantum cascade laser amplifier () having an active zone () includes a stack of raw layers of semi-conductor materials formed in an epitaxial manner on a substrate layer () of indium. phosphide (InP) or gallium arsenide (GaAs) bearing the active zone (), and a vertical anti-reflection coating () that covers an outlet face () of the laser radiation made of materials having given refraction indices and a predetermined thickness so that the entire laser radiation can flow through the outlet face. The anti-reflection coating () includes a first layer () having a first predetermined retraction index (n) lower than the predetermined refraction index (n), and at least a second layer () having a second refraction index (n) higher than the predetermined refraction index (n), wherein the first layer () of the anti-reflection coating () is made of yttrium fluoride (YF).

Quantum cascade laser amplifier with an anti-reflection coating including a layer of yttrium fluoride

Quantum cascade laser especially comprising a gain region () formed from several layers () which each comprise: The layers of the gain region () each constitute an active region extending from one to the other of the injection barriers () which are adjacent to it. The strata () are dimensioned such that:

Quantum cascade laser

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Zurich, Switzerland

Jérôme Faist