Now showing items 21-40 of 61

    • Generation of nearly nondiffracting Bessel beams with a Fabry–Perot interferometer 

      Horvath, Zoltan L.; Erdelyi, Miklos; Szabo, Gabor; Bor, Zs.; Tittel, Frank K.; Cavallaro, Joseph R. (1997-11-01)
      A new concept for generating zero-order Bessel beams was studied theoretically. The spatial intensity distribution was calculated numerically using a wave optics model. Approximate analytical expressions were derived to ...
    • Highly sensitive gas leak detector based on a quartz-enhanced photoacoustic SF6 sensor 

      Sampaolo, Angelo; Patimisco, Pietro; Giglio, Marilena; Chieco, Leonardo; Scamarcio, Gaetano; Tittel, Frank K.; Spagnolo, Vincenzo (2016)
      The implementation, performance validation, and testing of a gas-leak optical sensor based on mid-IR quartz-enhanced photoacoustic (QEPAS) spectroscopic technique is reported. A QEPAS sensor was integrated in a vacuum-sealed ...
    • Hydrogen peroxide detection with quartz-enhanced photoacoustic spectroscopy using a distributed-feedback quantum cascade laser 

      Ren, Wei; Jiang, Wenzhe; Sanchez, Nancy P.; Patimisco, Pietro; Spagnolo, Vincenzo; Zah, Chung-en; Xie, Feng; Hughes, Lawrence C.; Griffin, Robert J.; Tittel, Frank K. (2014)
      A quartz-enhanced photoacoustic spectroscopy sensor system was developed for the sensitive detection of hydrogen peroxide (H2O2) using its absorption transitions in the v6 fundamental band at ∼7.73 μm. The recent availability ...
    • Improved Tuning Fork for Terahertz Quartz-Enhanced Photoacoustic Spectroscopy 

      Sampaolo, Angelo; Patimisco, Pietro; Giglio, Marilena; Vitiello, Miriam S.; Beere, Harvey E.; Ritchie, David A.; Scamarcio, Gaetano; Tittel, Frank K.; Spagnolo, Vincenzo (2016)
      We report on a quartz-enhanced photoacoustic (QEPAS) sensor for methanol (CH₃OH) detection employing a novel quartz tuning fork (QTF), specifically designed to enhance the QEPAS sensing performance in the terahertz (THz) ...
    • An Integrated CAD Framework Linking VLSI Layout Editors and Process Simulators 

      Sengupta, Chaitali; Erdelyi, Miklos; Bor, Zsolt; Cavallaro, Joseph R.; Smayling, Michael C.; Szabo, Gabor; Tittel, Frank K.; Wilson, William L. (1996-03-01)
      As feature sizes in VLSI circuits extend into the far sub-micron range, new process techniques, such as using phase shifting masks for photolithography, will be needed. Under these conditions, the only means for the circuit ...
    • Interferometric Phase Shift Technique for High Resolution Deep UV Microlithography 

      Tittel, Frank K.; Cavallaro, Joseph R.; Kido, Motoi; Smayling, Michael C.; Szabo, Gabor; Wilson, William L. (1994-09-01)
      A new phase shifting technique based on interferometry has been developed which is especially suited for deep-UV microlithography. Using only a single layer chromium mask, with no additional phase shift elements, significant ...
    • Low power consumption quartz-enhanced photoacoustic gas sensor employing a quantum cascade laser in pulsed operation 

      Sampaolo, Angelo; Patimisco, Pietro; Gluszek, Aleksander; Hudzikowski, Arkadiusz; Giglio, Marilena; Zheng, Huadan; Tittel, Frank K.; Spagnolo, Vincenzo (2017)
      We report here an analysis of the performance of a quartz-enhanced photoacoustic (QEPAS) system operating in a pulsed mode by employing a quantum cascade laser (QCL). The QEPAS system is based on a quartz tuning fork (QTF) ...
    • Low-loss and single-mode tapered hollow-core waveguides optically coupled with interband and quantum cascade lasers 

      Giglio, Marilena; Patimisco, Pietro; Sampaolo, Angelo; Kriesel, Jason M.; Tittel, Frank K.; Spagnolo, Vincenzo (2018)
      We report single-mode midinfrared laser beam delivery through a 50-cm-long tapered hollow-core waveguide (HCW) having bore diameter linearly increasing from 200 to 260  μm. We performed theoretical calculations to identify ...
    • Low-Loss Coupling of Quantum Cascade Lasers into Hollow-Core Waveguides with Single-Mode Output in the 3.7–7.6 μm Spectral Range 

      Patimisco, Pietro; Sampaolo, Angelo; Mihai, Laura; Giglio, Marilena; Kriesel, Jason; Sporea, Dan; Scamarcio, Gaetano; Tittel, Frank K.; Spagnolo, Vincenzo (2016)
      We demonstrated low-loss and single-mode laser beam delivery through hollow-core waveguides (HCWs) operating in the 3.7–7.6 μm spectral range. The employed HCWs have a circular cross section with a bore diameter of 200 μm ...
    • Mid infrared quantum cascade laser operating in pure amplitude modulation for background-free trace gas spectroscopy 

      Bidaux, Yves; Bismuto, Alfredo; Patimisco, Pietro; Sampaolo, Angelo; Gresch, Tobias; Strubi, Gregory; Blaser, Stéphane; Tittel, Frank K.; Spagnolo, Vincenzo; Muller, Antoine; Faist, Jérôme (2016)
      We present a single mode multi-section quantum cascade laser source composed of three different sections: master oscillator, gain and phase section. Non-uniform pumping of the QCL’s gain reveals that the various laser ...
    • Mid-infrared dual-gas sensor for simultaneous detection of methane and ethane using a single continuous-wave interband cascade laser 

      Ye, Weilin; Li, Chunguang; Zheng, Chuantao; Sanchez, Nancy P.; Gluszek, Aleksander K.; Hudzikowski, Arkadiusz J.; Dong, Lei; Griffin, Robert J.; Tittel, Frank K. (2016)
      A continuous-wave (CW) interband cascade laser (ICL) based mid-infrared sensor system was demonstrated for simultaneous detection of atmospheric methane (CH4) and ethane (C2H6). A 3.337 µm CW ICL with an emitting wavenumber ...
    • Mid-Infrared Trace Gas Sensor Technology Based on Intracavity Quartz-Enhanced Photoacoustic Spectroscopy 

      Wojtas, Jacek; Gluszek, Aleksander; Hudzikowski, Arkadiusz; Tittel, Frank K. (2017)
      The application of compact inexpensive trace gas sensor technology to a mid-infrared nitric oxide (NO) detectoion using intracavity quartz-enhanced photoacoustic spectroscopy (I-QEPAS) is reported. A minimum detection limit ...
    • Multi-quartz-enhanced photoacoustic spectroscopy 

      Ma, Yufei; Yu, Xin; Yu, Guang; Li, Xudong; Zhang, Jingbo; Chen, Deying; Sun, Rui; Tittel, Frank K. (2015)
      A multi-quartz-enhanced photoacoustic spectroscopy (M-QEPAS) sensor system for trace gas detection is reported. Instead of a single quartz tuning fork (QTF) as used in QEPAS technique, a dual QTF sensor platform was adopted ...
    • A near-infrared gas sensor system based on tunable laser absorption spectroscopy and its application to CH4/C2H2 detection 

      He, Qixin; Zheng, Chuantao; Liu, Huifang; Wang, Yiding; Tittel, Frank K. (2017)
      A near-infrared (NIR) dual-channel differential gas sensor system was experimentally demonstrated based on tunable laser absorption spectroscopy (TLAS) and wavelength modulation spectroscopy (WMS). The sensor consists of ...
    • New approaches in quartz-enhanced photoacoustic sensing 

      Sampaolo, Angelo; Patimisco, Pietro; Pennetta, Riccardo; Scamarcio, Gaetano; Tittel, Frank K. (2015)
      We report on the design and realization of custom quartz tuning forks with different geometries and sizes aimed to improve the photoacoustic effect in quartz-enhanced photoacoustic (QEPAS) sensor systems. A detailed analysis ...
    • A New Interferometric Phase-Shifting Technique for Sub-half-micron Laser Microlithography 

      Erdelyi, Miklos; Sengupta, Chaitali; Bor, Zsolt; Cavallaro, Joseph R.; Kido, Motoi; Smayling, Michael C.; Tittel, Frank K.; Wilson, William L.; Szabo, Gabor (1995-02-01)
      This paper reports recent progress in achieving sub-half-micron feature sizes with UV laser illumination based on a novel interferometric phase shifting (IPS) technique. In the IPS arrangement, the intensity and amount of ...
    • A New Phase Shifting Method for High Resolution Microlithography 

      Kido, Motoi; Cavallaro, Joseph R.; Szabo, Gabor; Wilson, William L.; Tittel, Frank K. (1994-01-01)
      One of the most promising lithographic technique for the future designs of DRAMs is the phase-shifting mask technique. Conventional phase shifting-masks, however, are difficult to fabricate as they require regions of ...
    • Nonlinear Dynamic Theory for Photorefractive Phase Hologram Formation 

      Kim, Dae M.; Shah, Rajiv R.; Rabson, Thomas A.; Tittel, Frank K. (1976-01-20)
      A nonlinar dynamic theory is developed for the formation of photorefractive volume phase holograms. A feedback mechanism existing between the photo-generated field and free electron density, treated explicitly yields the ...
    • Overtone resonance enhanced single-tube on-beam quartz enhanced photoacoustic spectrophone 

      Zheng, Huadan; Dong, Lei; Sampaolo, Angelo; Patimisco, Pietro; Ma, Weiguang; Zhang, Lei; Yin, Wangbao; Xiao, Liantuan; Spagnolo, Vincenzo; Jia, Suotang; Tittel, Frank K. (2016)
      A single-tube on-beam quartz enhanced photoacoustic spectroscopy (SO-QEPAS) spectrophone, which employs a custom-made quartz tuning fork (QTF) having a prong spacing of 700 μm and operating at the 1st overtone flexural ...
    • Planar Laser-Based QEPAS Trace Gas Sensor 

      Ma, Yufei; He, Ying; Chen, Cheng; Yu, Xin; Zhang, Jingbo; Peng, Jiangbo; Sun, Rui; Tittel, Frank K. (2016)
      A novel quartz enhanced photoacoustic spectroscopy (QEPAS) trace gas detection scheme is reported in this paper. A cylindrical lens was employed for near-infrared laser focusing. The laser beam was shaped as a planar line ...