Dual-frequency modulated heterodyne quartz-enhanced photoacoustic spectroscopy
Optics Express, 2023 A novel dual-frequency modulated heterodyne quartz-enhanced photoacoustic spectroscopy (DFH-QEPAS) was demonstrated for what we believe to be the first time in this study. In traditional H-QEPAS, the frequency of modulated sinusoidal wave has a frequency difference (Δf) with the resonance frequency (f0) of a quartz tuning fork (QTF).
Ziting Lang +5 more
openaire +2 more sources
Photonics, 2023 This research proposes a method for the simultaneous acquisition of the second harmonic (2f) signal of quartz-enhanced photoacoustic spectroscopy (QEPAS) and the first harmonic (1f) signal of quartz-enhanced photothermal spectroscopy (QEPTS) based on the
Hao Liu +5 more
doaj +1 more source
Continuous wave optical parametric oscillator for quartz-enhanced photoacoustic trace gas sensing [PDF]
, 2007 A continuous wave optical parametric oscillator, generating up to 300 mW idler output in the 3–4 μm wavelength region, and pumped by a fiber-amplified DBR diode laser is used for trace gas detection by means of quartz-enhanced photoacoustic spectroscopy (
A. Henderson +33 more
core +6 more sources
Compact sound-speed sensor for quartz enhanced photoacoustic spectroscopy based applications [PDF]
, 2015 A compact sound-speed sensor based on a phase difference method was developed. The sensor employs a U-shaped stainless steel tube with two holes located on its front and back ends, which serves as a sound wave guide.
Dong, Lei, Liu, Kun, Tittel, Frank K.
core +1 more source
Detection of Molecular Oxygen at Low Concentrations Using Quartz Enhanced Photoacoustic Spectroscopy
Sensors, 2010 Molecular oxygen is detected at low concentrations using photoacoustic spectroscopy despite its unfavorable photoacoustic properties. The system consists of a seed laser diode, a tapered amplifier and a quartz tuning fork based spectrophone, thus ...
Andreas Pohlkötter +3 more
doaj +1 more source
Sub-parts-per-trillion level sensitivity in trace gas detection by cantilever-enhanced photo-acoustic spectroscopy [PDF]
, 2018 An exceptional property of photo-acoustic spectroscopy is the zero-background in wavelength modulation configuration while the signal varies linearly as a function of absorbed laser power.
Halonen, Lauri +3 more
core +3 more sources
Spider Silk-Improved Quartz-Enhanced Conductance Spectroscopy for Medical Mask Humidity Sensing
Molecules, 2022 Spider silk is one of the hottest biomaterials researched currently, due to its excellent mechanical properties. This work reports a novel humidity sensing platform based on a spider silk-modified quartz tuning fork (SSM-QTF). Since spider silk is a kind
Leqing Lin +11 more
doaj +1 more source
A measurement strategy for non-dispersive ultra-violet detection of formaldehyde in indoor air: Spectral analysis and interferent gases [PDF]
, 2015 We have conducted an extensive review of published spectra in order to identify a region with potential for detection of formaldehyde in indoor air.
Davenport, John +3 more
core +1 more source
Photoacoustic Techniques for Trace Gas Sensing Based on Semiconductor Laser Sources
Sensors, 2009 The paper provides an overview on the use of photoacoustic sensors based on semiconductor laser sources for the detection of trace gases. We review the results obtained using standard, differential and quartz enhanced photoacoustic techniques.
Vincenzo Spagnolo +3 more
doaj +1 more source
Modeling thin-film piezoelectric polymer ultrasonic sensors [PDF]
, 2014 This paper presents a model suitable to design and characterize broadband thin film sensors based on piezoelectric polymers. The aim is to describe adequately the sensor behavior, with a reasonable number of parameters and based on well-known physical ...
Cardozo Santiago, Gustavo David +2 more
core +1 more source