Infrared physics最新文献

{"title":"A novel tunable infrared detector based on a quantum ballistic channel","authors":"L.E. Fedichkin,&nbsp;V.I. Ryzhii,&nbsp;V.V. V'Yurkov","doi":"10.1016/0020-0891(93)90081-H","DOIUrl":"10.1016/0020-0891(93)90081-H","url":null,"abstract":"<div><p>We consider the possibility of infrared signal detection using photon-induced intersubband scattering in a quantum ballistic channel (QBC). Our calculations show that light absorption in a QBC with a non-uniform narrowed end can lead to a photovoltaic effect. Using mode matching techniques, the photocurrent is obtained. Evaluations of the responsivity, detectivity and bandwidth of the proposed photovoltaic detector are favorable for practical applications.</p></div>","PeriodicalId":81524,"journal":{"name":"Infrared physics","volume":"34 5","pages":"Pages 477-480"},"PeriodicalIF":0.0,"publicationDate":"1993-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0020-0891(93)90081-H","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"53081968","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Length and pressure dependence of the tuning spectrum produced by CH3F double Raman lasers","authors":"Jerald R. Izatt ,&nbsp;Wolfgang Schatz ,&nbsp;Karl F. Renk","doi":"10.1016/0020-0891(93)90085-L","DOIUrl":"10.1016/0020-0891(93)90085-L","url":null,"abstract":"<div><p>We have measured the spectrum produced by a tunable Raman FIR laser operated in a single-pass waveguide configuration using waveguide lengths of 50, 120 and 200 cm. For each waveguide a range of pressures was used that brackets the pressure at which the maximum output occurs. For ν₃ R-branch transitions in ¹²CH₃F and ¹³CH₃F with 15 ⩽ <em>J</em> ⩽ 20, the shape of the interline spectral profile could be changed significantly with only a modest sacrifice of output power. Using a 200-cm waveguide, for example, the usual spectral asymmetry weighted towards the higher <em>J</em> number transition can be eliminated or reversed by controlling the pressure. A 4-level density matrix model that incorporates pump depletion and signal growth along the waveguide reproduces some of the trends displayed by the experimental data but is unable to account fully for the large observed changes in the interline spectral profile.</p></div>","PeriodicalId":81524,"journal":{"name":"Infrared physics","volume":"34 5","pages":"Pages 513-523"},"PeriodicalIF":0.0,"publicationDate":"1993-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0020-0891(93)90085-L","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"53082006","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"All-Nb thin film microbridge-type Josephson junction for submillimeter-wave detection","authors":"Nobumitsu Hirose,&nbsp;Yuichi Harada,&nbsp;Matsuo Sekine,&nbsp;Shigeru Yoshimori ,&nbsp;Mitsuo Kawamura","doi":"10.1016/0020-0891(93)90078-L","DOIUrl":"10.1016/0020-0891(93)90078-L","url":null,"abstract":"<div><p>A copolymer of methyl methacrylate (MMA) and 3-triethoxysilylpropyl methacrylate (ESPMA) was proposed as a positive-working electron beam (EB) resist of a new type. It was found that it had 4–10 times the resistance of polymethylmethacrylate (PMMA) against CBrF₃ plasma damage. The mechanism of etching Nb in reactive-ion-etching (RIE) was deciphered. Using the new EB resist and nanometer process technology, an all-Nb thin film microbridge was fabricated. It shows the a.c. Josephson effect, i.e. the Shapiro steps upto the 11th were observed under millimeter-wave (70 GHz) radiation. In addition the coherently working performance of the series array of these thin-film microbridges were observed definitively.</p></div>","PeriodicalId":81524,"journal":{"name":"Infrared physics","volume":"34 5","pages":"Pages 445-455"},"PeriodicalIF":0.0,"publicationDate":"1993-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0020-0891(93)90078-L","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"53081924","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Photoresponse of a miniaturized metal film bolometer to ultrashort mid- and far-infrared laser pulses","authors":"P.T. Lang ,&nbsp;K.F. Mast ,&nbsp;K.F. Renk ,&nbsp;W. Schatz","doi":"10.1016/0020-0891(93)90082-I","DOIUrl":"10.1016/0020-0891(93)90082-I","url":null,"abstract":"<div><p>We report on an investigation of a photoresponse induced in a novel, miniaturized low-noise metal resistor film bolometer when irradiated by ultrashort laser pulses (duration 100 ps to 200 ns) with wavelengths covering the mid- and far-infrared spectral ranges. Successful operation at room temperature was achieved and almost constant detectivity was found over the whole frequency range investigated (15–1100 cm⁻¹). The minimum detectable laser pulse energy was determined to be about 0.6 μ J (with an electronic bandwidth of 1 kHz). This high detectivity and the miniaturized dimensions afford the possibility of building detector arrays applicable in mid- and far-infrared spectroscopy.</p></div>","PeriodicalId":81524,"journal":{"name":"Infrared physics","volume":"34 5","pages":"Pages 481-486"},"PeriodicalIF":0.0,"publicationDate":"1993-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0020-0891(93)90082-I","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"53081984","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Depolarization of far infrared laser beams in inconel and alumina waveguides","authors":"G. Magyar,&nbsp;J. O'Rourke","doi":"10.1016/0020-0891(93)90088-O","DOIUrl":"10.1016/0020-0891(93)90088-O","url":null,"abstract":"","PeriodicalId":81524,"journal":{"name":"Infrared physics","volume":"34 5","pages":"Pages 543-545"},"PeriodicalIF":0.0,"publicationDate":"1993-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0020-0891(93)90088-O","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"53082049","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical analysis of the electron energy distribution function in a CO2 laser discharge","authors":"M. Makhlouf ,&nbsp;S. Sazhin ,&nbsp;C. Leys ,&nbsp;D. Toebaert ,&nbsp;P. Wild","doi":"10.1016/0020-0891(93)90086-M","DOIUrl":"10.1016/0020-0891(93)90086-M","url":null,"abstract":"<div><p>A new simplified approach to the numerical solution of the Boltzmann equation in a collisional plasma is suggested and applied to the plasma of the fast-axial-flow CO₂ laser. Our results of computation of the electron energy distribution function (EEDF) are shown to be consistent with the results of similar computations based on the ELENDIF package. It is pointed out that most superelastic collisions, dissociative attachment of CO₂, ionization of He, thermal translational motion of molecules and their rotation can be safely ignored in the computations of the EEDF. On the other hand the error in the estimate of the ratio of the external electric field to the molecular density is the main source of error in the computation of the EEDF.</p></div>","PeriodicalId":81524,"journal":{"name":"Infrared physics","volume":"34 5","pages":"Pages 525-532"},"PeriodicalIF":0.0,"publicationDate":"1993-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0020-0891(93)90086-M","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"53082024","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A broadband light collection system for ECE diagnostics on the FTU tokamak","authors":"P. Buratti,&nbsp;O. Tudisco,&nbsp;M. Zerbini","doi":"10.1016/0020-0891(93)90087-N","DOIUrl":"10.1016/0020-0891(93)90087-N","url":null,"abstract":"<div><p>Electron temperature profiles are currently measured on the FTU tokamak by spectral analysis of electron cyclotron emission. Light pipes are used for collecting the light and transporting it to a Fourier transform spectrometer and to a grating polychromator. Use of a light pipe facing the plasma allows one to obtain a large étendue in spite of the restricted diagnostic access, while a narrow field of view is defined by a quasi optical system placed outside the tokamak vacuum. The reliability of this combination of light pipes and quasi optical elements has been checked in the laboratory and has been confirmed by more than 3 years of routine operation on the FTU tokamak.</p></div>","PeriodicalId":81524,"journal":{"name":"Infrared physics","volume":"34 5","pages":"Pages 533-541"},"PeriodicalIF":0.0,"publicationDate":"1993-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0020-0891(93)90087-N","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"53082037","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Surface layers and far infrared spectra of High-Tc superconductors","authors":"Armand Hadni ,&nbsp;Xavier Gerbaux ,&nbsp;Masato Tazawa","doi":"10.1016/0020-0891(93)90084-K","DOIUrl":"https://doi.org/10.1016/0020-0891(93)90084-K","url":null,"abstract":"<div><p>It is possible to increase significantly the accuracy of far IR (FIR) transmission spectra of High-<em>T</em>c superconductors by depositing a very thin oriented film (e.g. <em>t</em> = 300 Å), of either YBaCuO or GdBaCuO on a very thin MgO plate (e.g. <em>t</em>₀ = 90 <em>μm</em>). Such very thin films of superconductors are unstable and FIR transmission either at 300 or 10 K increases dramatically after a few weeks. A phenomenological model is however possible to explain all spectra at different temperatures from 300 to 10 K if we consider a thin layer of insulating barium cuprate (e.g. GdBaCuO₆) made by a progressive loss of oxygen.</p><p>More precisely, for one sample with <em>T</em>_<em>c</em> = 88 <em>K</em>, and within the accuracy of the measurements, the plasma frequency<span><math><mtext>ν</mtext><msub><mi></mi><mn>p</mn></msub><mtext> = </mtext><mtext>1</mtext><mtext>2πc</mtext><mtext>(</mtext><mtext>N</mtext><msub><mi></mi><mn>0</mn></msub><mtext>e</mtext><msup><mi></mi><mn>2</mn></msup><mtext>mε</mtext><msub><mi></mi><mn>0</mn></msub><mtext>ε</mtext><msub><mi></mi><mn>R</mn></msub><mtext>)</mtext><msup><mi></mi><mn><mtext>1</mtext><mtext>2</mtext></mn></msup></math></span>, is a constant,<em>ν</em>_<em>p</em> = 4500 <em>cm</em>⁻¹, and ν_c is a linear function of temperature for <em>T</em> &gt;; <em>T</em>c (ν_c = 1.6 T + 55 cm⁻¹). For <em>T</em> &lt; <em>T</em>c, a <em>T</em>⁴ law has been used to get the number of quasiparticles in the superconductive phase and to compute the spectrum at <em>T</em> = 86 K with the additional assumption of a collision frequency saturating around 50cm⁻¹. We have also to introduce 3 mid-IR active oscillators at room temperature, and to keep them in the superconductive phase, with a definite increase in their strengths.</p><p>That phenomenological model contains 11 parameters only since we have shown the possibility to use only one plasma frequency at all temperatures and to adjust only one collision frequency (the one at very low temperature).</p></div>","PeriodicalId":81524,"journal":{"name":"Infrared physics","volume":"34 5","pages":"Pages 501-511"},"PeriodicalIF":0.0,"publicationDate":"1993-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0020-0891(93)90084-K","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"92031709","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Forthcoming conferences","authors":"","doi":"10.1016/0020-0891(93)90089-P","DOIUrl":"https://doi.org/10.1016/0020-0891(93)90089-P","url":null,"abstract":"","PeriodicalId":81524,"journal":{"name":"Infrared physics","volume":"34 5","pages":"Pages 547-548"},"PeriodicalIF":0.0,"publicationDate":"1993-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0020-0891(93)90089-P","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"92031710","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The influence of heat exchange between a sensitive element and its surroundings on the specific detectivity of pyroelectric detectors","authors":"N. Neumann ,&nbsp;S. Möhling","doi":"10.1016/0020-0891(93)90083-J","DOIUrl":"10.1016/0020-0891(93)90083-J","url":null,"abstract":"<div><p>The specific detectivity of pyroelectric sensors at low frequencies is mainly influenced by the thermal conditions within the sensor. The temperature noise caused by heat exchange between the sensitive element and its surroundings is transformed into an increase of the dielectric loss due to electrothermal coupling. The complex normalized current responsivity is used to calculate the influence of thermal conditions. While the absolute value ¦<em>T</em>_R¦ gives the frequency response of the sensitivity, the additional dielectric loss tan δ_T is deduced from the imaginary part. The loss due to electrothermal coupling tan δ_T exceeds the dielectric intrinsic loss tan δ_i for most sensor structures within the frequency range up to 100 Hz. Thus, the maximum attainable specific detectivity of a pyroelectric sensor at normal operation frequencies is dependent on its construction rather than on the material parameter dielectric intrinsic loss tan δ_i which is frequently referred to. The effect of electrothermal coupling can be employed in sensors with reduced sensitivity at low frequencies as used for FTIR-devices.</p></div>","PeriodicalId":81524,"journal":{"name":"Infrared physics","volume":"34 5","pages":"Pages 487-499"},"PeriodicalIF":0.0,"publicationDate":"1993-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0020-0891(93)90083-J","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"53081994","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}