Proceedings of SPIE - The International Society for Optical Engineering
We present a scheme for the realization of high performances, large tuning range, fully integrate... more We present a scheme for the realization of high performances, large tuning range, fully integrated and possibly low cost mid infrared laser source based on quantum cascade lasers and silicon based integrated optics. It is composed of a laser array and a laser combiner. We show that our metal grating approach gives many advantages for the fabrication yield of those laser arrays. We show the results of such a fabrication at 1350 cm-1 with 60 cm-1 tuning range. The silicon is a low cost option for the size consuming combiner. In the development of the SiGe platform, we present the loss measurement set up and we show losses below 1dB/cm at 4.5μm.
Physical review. B, Condensed matter, Jan 15, 1989
The electronic band structure of the InAs-GaSb superlattice is studied within the localized-orbit... more The electronic band structure of the InAs-GaSb superlattice is studied within the localized-orbital framework by the renormalization method. The tight-binding Hamiltonian includes spin-orbit coupling and an accurate description of the composing crystals near relevant band edges. The tight-binding renormalization-group method is described in detail, and is shown to be conceptually simple and operatively efficient. The superlattice band structure is calculated
We demonstrate the frequency doubling of a quantum cascade laser in a multilayered, partially oxi... more We demonstrate the frequency doubling of a quantum cascade laser in a multilayered, partially oxidized GaAs/AlOx waveguide. Using the waveguide width to fulfill the phase-matching condition, the second harmonic is generated in the wavelength range between 2.2 and 2.4 μm, where not many semiconductor sources are commercially available to date. We discuss the impact of a few fabrication and experimental parameters on the conversion efficiency, an essential step toward the improvement and practical implementation of this proof-of-principle semiconductor microsystem.
Conference on Lasers and Electro-Optics/International Quantum Electronics Conference, 2009
ABSTRACT We report an efficient technique to measure gain and losses of quantum cascade lasers (Q... more ABSTRACT We report an efficient technique to measure gain and losses of quantum cascade lasers (QCLs). It consists on the analysis of the Fabry-Perot fringes induced by the optical injection of a chirped distributed feedback QCL.
2014 IEEE Joint Intelligence and Security Informatics Conference, 2014
ABSTRACT Abstract— Border security is one of the key challenges to be taken up by Europe in the f... more ABSTRACT Abstract— Border security is one of the key challenges to be taken up by Europe in the following years. In particular, the deployment of practical efficient means to detect hidden persons and illegal substances at border crossing points is instrumental in avoiding terrorism, human trafficking or smuggling. This study presents the concept of an “orthogonal” approach to the identification of gas traces identified as pertinent targets for illicit substances (drugs and explosives) as well as for human presence. The techniques employed to perform the analysis are based on completely different physical principles; these are the Mid-Infrared photo-acoustic spectroscopy (MIR-PAS - demonstration of a novel widely tunable integrated MIR source coupled with a miniature photo-acoustic cell) and the Ion mobility spectrometry (IMS) using a non radio-active ionization source. Definition of the pertinent compounds and their “spectral signature” (characterized with recording of the vapour phase IR properties via GC-FTIR and GC-MS), lead to a database of the target substances; the IR wavelengths were selected based on the individual target. For the case of human presence, volatile fatty acids (VFA) present in human sweat identified as ideal targets for remote detection of hidden persons; for example some VFAs are human specific, such as HMHA and 3MHA. The aforementioned VFAs are also active in the MIR range. Similarly for the case of the illicit drugs targeting has been based on their emitted VOCs depending on the type of substance (e.g. alkaloid drugs associated with their volatile degradation products etc); during this study, characterization of the cannabis markers lead to the identification of a new marker (under revision for European patent). For explosives substances volatile taggants are mainly associated with VOCs available during their preparation. In total 58 volatile organic compounds (VOCs) were identified in this study as candidates for the detection of Humans (31), Illegal Drugs (19), and Explosives (13). The aforementioned spectral database has been employed for algorithm selection and training; the algorithms used were the Support Vector Machines (SVM), Partial Least Squares – Discrimant Analysis (PLS – DA) and the k – Nearest Neighbour (KNN); the results are very promising reaching levels of matching during training up to 98%. These algorithms will fuse the data collected and analysed by the two powerful techniques selected as the components of this « orthogonal » approach to the detection of the aforementioned gas traces. Target specific cavitand receptors were developed for the pre-concentrator procedure that increase the concentration of the gas trace in quest. During this work, improvement to the pre-concentration configuration has reduced the required time for the pre-concentration procedure significantly (10s of seconds compared to several minutes); this is part of the novelties developed during this study. IMS studies for detection of human presence has shown very promising results, recording levels of human specific gas traces after 15 minutes of a human present in an area of 50m3. This is very important considering that in most cases the people illegaly immigrating are confined in much smaller spaces and for very much longer periods (most of the times are more than one person too) which leads to increased concentration and abundance of the related VOCs hence, the instrument will definetely perform better. A miniaturized MIR-PAS has been developed supported by an array of DFB-QCLs that allows for this instrument to be a portable solution for operators at border points, assisting their daily activities and increase their performance. This is a powerful and promising tool to detect a very wide range of volatile organic compounds (VOCs). Keywords—Border security, Orthogonal Technologies, IMS, MIRPAS, Human Detection, Illicit Drugs, Explosives, Olfactory, Mobile Instrument
2013 Conference on Lasers & Electro-Optics Europe & International Quantum Electronics Conference CLEO EUROPE/IQEC, 2013
ABSTRACT We present the realizations of an array of Distributed Feedback (DFB) lasers and passive... more ABSTRACT We present the realizations of an array of Distributed Feedback (DFB) lasers and passive optical waveguides based on Silicon. The aim of these preliminary results is to realize a monolithic, widely tuneable, source in the mid-Infrared (mIR) for laser spectroscopy.
2013 Conference on Lasers & Electro-Optics Europe & International Quantum Electronics Conference CLEO EUROPE/IQEC, 2013
ABSTRACT form only given. For optical countermeasures application, the efficiency of the sources,... more ABSTRACT form only given. For optical countermeasures application, the efficiency of the sources, the beam quality and the power are the crucial points. In the field of quantum cascade lasers, those three parameters give trade off values on the geometry of the laser limiting seriously the capability of the technology. For instance, one has to use ridges with width below 8μm to have a M2 suitable for DIRCM application. It limits the power to 5W up to now [1]. We will introduce a new way to improve the power of the laser while keeping a good beam quality: μ-stripes array technology (see fig 2) [2]. These buried arrays are very appealing because they offer both lateral dissipation enhancement and beam quality control in large active region lasers.We will present the numerical modeling of this μ-stripes approach analyzing the beam quality and the thermal properties. We will show that the thermal resistance is not any more limited by the active regions materials and demonstrate thermal resistances below 2 K/W, as shown on figure 1. Comparison between experimental and theoretical results show excellent agreement allows us to make prediction on the possibility of this technology. Thermal resistance decreases with both number and width of emitters. Furthermore we have also shown in previous work phase-locking provided by evanescent coupling between adjacent ridges and singlemode emission up to 32 emitters [3]. By analyzing the beam quality we show that the laser is 100% coherent and spatially mono-mode.
ABSTRACT Together with the optimal basic design, buried heterostructure quantum cascade laser (BH... more ABSTRACT Together with the optimal basic design, buried heterostructure quantum cascade laser (BH-QCL) with semi-insulating regrowth offers unique possibility to achieve an effective thermal dissipation and lateral single mode. We demonstrate here for the first time realization of BH-QCLs with a single step regrowth of highly resistive (<1x108 ohm•cm) semiinsulating InP:Fe in less than 45 minutes in a flexible hydride vapour phase epitaxy process for burying ridges etched down to 10-15 μm deep both with and without mask overhang. The fabricated BH-QCLs emitting at ~4.7 μm and ~5.5 μm were characterized. 2 mm long 5.5 μm lasers with ridge width 17-22 μm, regrown with mask overhang, exhibited no leakage current. Large width and high doping in the structure did not permit high current density for CW operation. 5 mm long 4.7 μm BH-QCLs of ridge widths varying from 6-14 μm regrown without mask overhang, besides being spatially monomode, TM00, exhibited WPE of ~8-9% with an output power of 1.5 – 2.5 W at room temperature and under CW operation. Thus, we demonstrate a simple, flexible, quick, stable and single-step regrowth process with extremely good planarization for realizing buried QCLs leading to monomode, high power and high WPE.
... aAuthor to whom correspondence should be addressed. Electronic mail: amandine.buffaz@gmail. c... more ... aAuthor to whom correspondence should be addressed. Electronic mail: amandine.buffaz@gmail. com. -0.1 -0.2 -0.3 Width (Å) Band offset (eV ) ... Phys. Lett. 86, 121116 2005. 8M. Graf, N. Hoyler, M. Giovannini, J. Faist, and D. Hofstetter, Appl. Phys. Lett. 88, 241118 2006. 9F. ...
... superlattices. We can moreover consider the diffusion between and being fast as compared to t... more ... superlattices. We can moreover consider the diffusion between and being fast as compared to the Rabi time , with the coupling energy between subbands and . ... 6, 120 (1972). Author to whom correspondence should be addressed. Electronic mail: amandine.buffaz@gmail.com. ...
Proceedings of SPIE - The International Society for Optical Engineering
We present a scheme for the realization of high performances, large tuning range, fully integrate... more We present a scheme for the realization of high performances, large tuning range, fully integrated and possibly low cost mid infrared laser source based on quantum cascade lasers and silicon based integrated optics. It is composed of a laser array and a laser combiner. We show that our metal grating approach gives many advantages for the fabrication yield of those laser arrays. We show the results of such a fabrication at 1350 cm-1 with 60 cm-1 tuning range. The silicon is a low cost option for the size consuming combiner. In the development of the SiGe platform, we present the loss measurement set up and we show losses below 1dB/cm at 4.5μm.
Physical review. B, Condensed matter, Jan 15, 1989
The electronic band structure of the InAs-GaSb superlattice is studied within the localized-orbit... more The electronic band structure of the InAs-GaSb superlattice is studied within the localized-orbital framework by the renormalization method. The tight-binding Hamiltonian includes spin-orbit coupling and an accurate description of the composing crystals near relevant band edges. The tight-binding renormalization-group method is described in detail, and is shown to be conceptually simple and operatively efficient. The superlattice band structure is calculated
We demonstrate the frequency doubling of a quantum cascade laser in a multilayered, partially oxi... more We demonstrate the frequency doubling of a quantum cascade laser in a multilayered, partially oxidized GaAs/AlOx waveguide. Using the waveguide width to fulfill the phase-matching condition, the second harmonic is generated in the wavelength range between 2.2 and 2.4 μm, where not many semiconductor sources are commercially available to date. We discuss the impact of a few fabrication and experimental parameters on the conversion efficiency, an essential step toward the improvement and practical implementation of this proof-of-principle semiconductor microsystem.
Conference on Lasers and Electro-Optics/International Quantum Electronics Conference, 2009
ABSTRACT We report an efficient technique to measure gain and losses of quantum cascade lasers (Q... more ABSTRACT We report an efficient technique to measure gain and losses of quantum cascade lasers (QCLs). It consists on the analysis of the Fabry-Perot fringes induced by the optical injection of a chirped distributed feedback QCL.
2014 IEEE Joint Intelligence and Security Informatics Conference, 2014
ABSTRACT Abstract— Border security is one of the key challenges to be taken up by Europe in the f... more ABSTRACT Abstract— Border security is one of the key challenges to be taken up by Europe in the following years. In particular, the deployment of practical efficient means to detect hidden persons and illegal substances at border crossing points is instrumental in avoiding terrorism, human trafficking or smuggling. This study presents the concept of an “orthogonal” approach to the identification of gas traces identified as pertinent targets for illicit substances (drugs and explosives) as well as for human presence. The techniques employed to perform the analysis are based on completely different physical principles; these are the Mid-Infrared photo-acoustic spectroscopy (MIR-PAS - demonstration of a novel widely tunable integrated MIR source coupled with a miniature photo-acoustic cell) and the Ion mobility spectrometry (IMS) using a non radio-active ionization source. Definition of the pertinent compounds and their “spectral signature” (characterized with recording of the vapour phase IR properties via GC-FTIR and GC-MS), lead to a database of the target substances; the IR wavelengths were selected based on the individual target. For the case of human presence, volatile fatty acids (VFA) present in human sweat identified as ideal targets for remote detection of hidden persons; for example some VFAs are human specific, such as HMHA and 3MHA. The aforementioned VFAs are also active in the MIR range. Similarly for the case of the illicit drugs targeting has been based on their emitted VOCs depending on the type of substance (e.g. alkaloid drugs associated with their volatile degradation products etc); during this study, characterization of the cannabis markers lead to the identification of a new marker (under revision for European patent). For explosives substances volatile taggants are mainly associated with VOCs available during their preparation. In total 58 volatile organic compounds (VOCs) were identified in this study as candidates for the detection of Humans (31), Illegal Drugs (19), and Explosives (13). The aforementioned spectral database has been employed for algorithm selection and training; the algorithms used were the Support Vector Machines (SVM), Partial Least Squares – Discrimant Analysis (PLS – DA) and the k – Nearest Neighbour (KNN); the results are very promising reaching levels of matching during training up to 98%. These algorithms will fuse the data collected and analysed by the two powerful techniques selected as the components of this « orthogonal » approach to the detection of the aforementioned gas traces. Target specific cavitand receptors were developed for the pre-concentrator procedure that increase the concentration of the gas trace in quest. During this work, improvement to the pre-concentration configuration has reduced the required time for the pre-concentration procedure significantly (10s of seconds compared to several minutes); this is part of the novelties developed during this study. IMS studies for detection of human presence has shown very promising results, recording levels of human specific gas traces after 15 minutes of a human present in an area of 50m3. This is very important considering that in most cases the people illegaly immigrating are confined in much smaller spaces and for very much longer periods (most of the times are more than one person too) which leads to increased concentration and abundance of the related VOCs hence, the instrument will definetely perform better. A miniaturized MIR-PAS has been developed supported by an array of DFB-QCLs that allows for this instrument to be a portable solution for operators at border points, assisting their daily activities and increase their performance. This is a powerful and promising tool to detect a very wide range of volatile organic compounds (VOCs). Keywords—Border security, Orthogonal Technologies, IMS, MIRPAS, Human Detection, Illicit Drugs, Explosives, Olfactory, Mobile Instrument
2013 Conference on Lasers & Electro-Optics Europe & International Quantum Electronics Conference CLEO EUROPE/IQEC, 2013
ABSTRACT We present the realizations of an array of Distributed Feedback (DFB) lasers and passive... more ABSTRACT We present the realizations of an array of Distributed Feedback (DFB) lasers and passive optical waveguides based on Silicon. The aim of these preliminary results is to realize a monolithic, widely tuneable, source in the mid-Infrared (mIR) for laser spectroscopy.
2013 Conference on Lasers & Electro-Optics Europe & International Quantum Electronics Conference CLEO EUROPE/IQEC, 2013
ABSTRACT form only given. For optical countermeasures application, the efficiency of the sources,... more ABSTRACT form only given. For optical countermeasures application, the efficiency of the sources, the beam quality and the power are the crucial points. In the field of quantum cascade lasers, those three parameters give trade off values on the geometry of the laser limiting seriously the capability of the technology. For instance, one has to use ridges with width below 8μm to have a M2 suitable for DIRCM application. It limits the power to 5W up to now [1]. We will introduce a new way to improve the power of the laser while keeping a good beam quality: μ-stripes array technology (see fig 2) [2]. These buried arrays are very appealing because they offer both lateral dissipation enhancement and beam quality control in large active region lasers.We will present the numerical modeling of this μ-stripes approach analyzing the beam quality and the thermal properties. We will show that the thermal resistance is not any more limited by the active regions materials and demonstrate thermal resistances below 2 K/W, as shown on figure 1. Comparison between experimental and theoretical results show excellent agreement allows us to make prediction on the possibility of this technology. Thermal resistance decreases with both number and width of emitters. Furthermore we have also shown in previous work phase-locking provided by evanescent coupling between adjacent ridges and singlemode emission up to 32 emitters [3]. By analyzing the beam quality we show that the laser is 100% coherent and spatially mono-mode.
ABSTRACT Together with the optimal basic design, buried heterostructure quantum cascade laser (BH... more ABSTRACT Together with the optimal basic design, buried heterostructure quantum cascade laser (BH-QCL) with semi-insulating regrowth offers unique possibility to achieve an effective thermal dissipation and lateral single mode. We demonstrate here for the first time realization of BH-QCLs with a single step regrowth of highly resistive (<1x108 ohm•cm) semiinsulating InP:Fe in less than 45 minutes in a flexible hydride vapour phase epitaxy process for burying ridges etched down to 10-15 μm deep both with and without mask overhang. The fabricated BH-QCLs emitting at ~4.7 μm and ~5.5 μm were characterized. 2 mm long 5.5 μm lasers with ridge width 17-22 μm, regrown with mask overhang, exhibited no leakage current. Large width and high doping in the structure did not permit high current density for CW operation. 5 mm long 4.7 μm BH-QCLs of ridge widths varying from 6-14 μm regrown without mask overhang, besides being spatially monomode, TM00, exhibited WPE of ~8-9% with an output power of 1.5 – 2.5 W at room temperature and under CW operation. Thus, we demonstrate a simple, flexible, quick, stable and single-step regrowth process with extremely good planarization for realizing buried QCLs leading to monomode, high power and high WPE.
... aAuthor to whom correspondence should be addressed. Electronic mail: amandine.buffaz@gmail. c... more ... aAuthor to whom correspondence should be addressed. Electronic mail: amandine.buffaz@gmail. com. -0.1 -0.2 -0.3 Width (Å) Band offset (eV ) ... Phys. Lett. 86, 121116 2005. 8M. Graf, N. Hoyler, M. Giovannini, J. Faist, and D. Hofstetter, Appl. Phys. Lett. 88, 241118 2006. 9F. ...
... superlattices. We can moreover consider the diffusion between and being fast as compared to t... more ... superlattices. We can moreover consider the diffusion between and being fast as compared to the Rabi time , with the coupling energy between subbands and . ... 6, 120 (1972). Author to whom correspondence should be addressed. Electronic mail: amandine.buffaz@gmail.com. ...
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