scholarly journals A Fabry–Perot interferometer-based camera for two-dimensional mapping of SO<sub>2</sub> distributions

2014 ◽  
Vol 7 (11) ◽  
pp. 3705-3715 ◽  
Author(s):  
J. Kuhn ◽  
N. Bobrowski ◽  
P. Lübcke ◽  
L. Vogel ◽  
U. Platt
Keyword(s):  
Theoretical Study ◽  
Point Sources ◽  
Imaging Method ◽  
Absorption Bands ◽  
Present Sample ◽  
Camera Systems ◽  
Fabry Perot ◽  
Band Absorption ◽  
Atmospheric Radiative Transfer ◽  
Dimensional Mapping

Abstract. We examine a new imaging method for the remote sensing of volcanic gases, which relies on the regularly spaced narrow-band absorption structures in the UV–VIS of many molecules. A Fabry–Perot interferometer (FPI) is used to compare the scattered sunlight radiance at wavelengths corresponding to absorption bands with the radiance at wavelengths in between the bands, thereby identifying and quantifying the gas. In this first theoretical study, we present sample calculations for the detection of sulfur dioxide (SO2). Optimum values for the FPI setup parameters are proposed. Furthermore, the performance of the FPI method is compared to SO2 cameras. We show that camera systems using an FPI are far less influenced by changes in atmospheric radiative transfer (e.g., due to aerosol) and have a great potential as a future technique for examining emissions of SO2 (or other gases) from volcanic sources and other point sources.

scholarly journals A Fabry–Perot interferometer based camera for two-dimensional mapping of SO<sub>2</sub> distributions

2014 ◽  
Vol 7 (5) ◽  
pp. 5117-5145 ◽  
Author(s):  
J. Kuhn ◽  
N. Bobrowski ◽  
P. Lübcke ◽  
L. Vogel ◽  
U. Platt
Keyword(s):  
Point Sources ◽  
Imaging Method ◽  
Absorption Bands ◽  
Present Sample ◽  
Camera Systems ◽  
Fabry Perot ◽  
Band Absorption ◽  
Atmospheric Radiative Transfer ◽  
Set Up ◽  
Dimensional Mapping

Abstract. We examine a new imaging method for the remote sensing of volcanic gases, which relies on the regularly spaced narrow-band absorption structures in the UV-VIS of many molecules. A Fabry–Perot interferometer (FPI) is used to compare the scattered sunlight radiance at wavelengths corresponding to absorption bands with the radiance at wavelengths in between the bands, thereby identifying and quantifying the gas. In this first theoretical study, we present sample calculations for the detection of sulfur dioxide (SO2). Optimum values for the FPI set-up parameters are proposed. Further, the performance of the FPI method is compared to SO2 cameras. We show that camera systems using a FPI are far less influenced by changes in atmospheric radiative transfer (e.g. due to aerosol) and have a great potential as a future technique to examine emissions of SO2 (or other gases) from volcanic sources and other point sources.

scholarly journals Numerical Study of Angle-Insensitive and Tunable Dual-Band THz Absorber Using Periodic Cross-Shaped Graphene Arrays

Materials ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2063 ◽  
Author(s):  
Tian Sang ◽  
Jian Gao ◽  
La Wang ◽  
Honglong Qi ◽  
Xin Yin ◽  
...  
Keyword(s):  
Transverse Electric ◽  
Numerical Study ◽  
Transverse Magnetic ◽  
Dual Band ◽  
Absorption Enhancement ◽  
Cavity Model ◽  
Absorption Bands ◽  
Fabry Perot ◽  
Band Absorption ◽  
The Cross

A dual-band terahertz (THz) absorber using the periodic cross-shaped graphene arrays is presented. It is shown that the dual-band light absorption enhancement of graphene results from the edge graphene plasmon (EGP) resonance, and the locations of the two absorption peaks can be precisely estimated by using the Fabry-Pérot (F-P) cavity model. Slight residual reflection remains at the two absorption peaks because the input impedance of the cross-arm cannot be perfectly matched with the free space impedance. In addition, the locations of the two absorption bands can be simultaneously tuned by changing the Fermi level of graphene, and they can be independently tuned by changing the width or the length of the cross-arm of graphene. Excellent angle-insensitivity dual-band absorption enhancement of graphene can be maintained for both the transverse electric (TE) and transverse magnetic (TM) polarizations.

scholarly journals Broadband Absorption in Patterned Metal/Weakly-Absorbing-Spacer/Metal with Graded Photonic Super-Crystal

Photonics ◽  
2021 ◽  
Vol 8 (4) ◽  
pp. 114
Author(s):  
Steve Kamau ◽  
Safaa Hassan ◽  
Khadijah Alnasser ◽  
Hualiang Zhang ◽  
Jingbiao Cui ◽  
...  
Keyword(s):  
Surface Plasmon ◽  
Surface Plasmon Polariton ◽  
Near Infrared ◽  
Broadband Absorption ◽  
Au Film ◽  
Fabry Perot ◽  
Absorbing Material ◽  
Multiple Band ◽  
Band Absorption ◽  
Plasmon Polaritons

It is challenging to realize the complete broadband absorption of near-infrared in thin optical devices. In this paper, we studied high light absorption in two devices: a stack of Au-pattern/insulator/Au-film and a stack of Au-pattern/weakly-absorbing-material/Au-film where the Au-pattern was structured in graded photonic super-crystal. We observed multiple-band absorption, including one near 1500 nm, in a stack of Au-pattern/spacer/Au-film. The multiple-band absorption is due to the gap surface plasmon polariton when the spacer thickness is less than 30 nm. Broadband absorption appears in the near-infrared when the insulator spacer is replaced by a weakly absorbing material. E-field intensity was simulated and confirmed the formation of gap surface plasmon polaritons and their coupling with Fabry–Pérot resonance.

scholarly journals Study of Utilization of Embedded Metal Nanoparticles in Dielectric Thin Film for Humidity Sensing

2019 ◽  
Vol 10 (2) ◽  
pp. 155-161
Author(s):  
Hala J. El-Khozondar ◽  
Waleed S. Mohammed
Keyword(s):  
Metal Nanoparticles ◽  
Theoretical Study ◽  
Dynamic Range ◽  
Volume Fraction ◽  
Dielectric Thin Film ◽  
Reflected Light ◽  
Metal Type ◽  
Reflection Peak ◽  
Fabry Perot ◽  
Film Interface

Abstract This paper presents a theoretical study of the utilization of the shift in the reflection peak of the thin dielectric film with embedded metal nanoparticles (NPs) towards humidity and vapor applications. The presence of the NPs in the film results in a complex effective index. Hence, the reflected light at the superstrate-film interface causes a phase shift when the index of the surrounding is changed. This alters the reflected spectrum of the formed Fabry-Perot, for both the reflection peak wavelength and intensity. Here, the dynamic range of the proposed sensor is optimized through the variation of the film thickness and nanoparticle metal type, as well as the volume fraction.

Highly efficient narrow-band absorption of a graphene-based Fabry–Perot structure at telecommunication wavelengths

2019 ◽  
Vol 44 (14) ◽  
pp. 3430 ◽  
Author(s):  
Kun Zhou ◽  
Qiang Cheng ◽  
Jinlin Song ◽  
Lu Lu ◽  
Zixue Luo
Keyword(s):  
Narrow Band ◽  
Highly Efficient ◽  
Fabry Perot ◽  
Band Absorption

Theoretical study of an actively mode-locked fiber laser stabilized by an intracavity Fabry-Perot etalon: linear regime

2007 ◽  
Vol 24 (8) ◽  
pp. 1793 ◽  
Author(s):  
Yurij Parkhomenko ◽  
Moshe Horowitz ◽  
Curtis R. Menyuk ◽  
Thomas F. Carruthers
Keyword(s):  
Fiber Laser ◽  
Theoretical Study ◽  
Linear Regime ◽  
Fabry Perot

Coherent anti-Stokes Raman scattering in a Fabry-Perot cavity: A theoretical study

2009 ◽  
Vol 26 (7) ◽  
pp. 1295 ◽  
Author(s):  
Franck Billard ◽  
David Gachet ◽  
Hervé Rigneault
Keyword(s):  
Raman Scattering ◽  
Theoretical Study ◽  
Fabry Perot ◽  
Anti Stokes

scholarly journals Bias assessment of lower and middle tropospheric CO<sub>2</sub> concentrations of GOSAT/TANSO-FTS TIR Version 1 product

2017 ◽  
Author(s):  
Naoko Saitoh ◽  
Shuhei Kimoto ◽  
Ryo Sugimura ◽  
Ryoichi Imasu ◽  
Kei Shiomi ◽  
...  
Keyword(s):  
Bias Correction ◽  
Lower Troposphere ◽  
Point Sources ◽  
Upper Atmosphere ◽  
Retrieval Algorithm ◽  
Co2 Absorption ◽  
Free Troposphere ◽  
Absorption Bands ◽  
Co2 Concentrations ◽  
Local Point

Abstract. CO2 observations in the free troposphere can be useful for constraining CO2 source and sink estimates at the surface due to their representativeness being away from local point sources of CO2. The thermal infrared (TIR) band of the Thermal and Near Infrared Sensor for Carbon Observation (TANSO)−Fourier Transform Spectrometer (FTS) on board the Greenhouse Gases Observing Satellite (GOSAT) has been observing global CO2 concentrations in the free troposphere for about 8 years, and thus could provide a dataset with which to evaluate the vertical transport of CO2 from the surface to the upper atmosphere. This study evaluated biases in the TIR version 1 (V1) CO2 product in the lower troposphere (LT) and the middle troposphere (MT) (736–287 hPa), on the basis of comparisons with CO2 profiles obtained over airports using Continuous CO2 Measuring Equipment (CME) in the Comprehensive Observation Network for Trace gases by AIrLiner (CONTRAIL) project. Bias-correction values are presented for TIR CO2 data for each pressure layer in the LT and MT regions during each season and in each latitude band: 40°S–20°S, 20° S–20° N, 20° N–40° N, and 40° N–60° N. TIR V1 CO2 data had consistent negative biases of 1–1.5 % compared with CME CO2 data in the LT and MT regions, with the largest negative biases at 541–398 hPa, partly due to the use of 10-μm CO2 absorption band in conjunction with 15-μm and 9-μm absorption bands in the V1 retrieval algorithm. Global comparisons between TIR CO2 data to which the bias-correction values were applied and CO2 data simulated by Nonhydrostatic ICosahedral Atmospheric Model (NICAM)-based transport model (TM) confirmed the validity of the bias-correction values evaluated over airports in limited areas. In low latitudes in the upper MT region (398–287 hPa), however, TIR CO2 data in northern summer were overcorrected by these bias-correction values; this is because the bias-correction values were determined using comparisons mainly over airports in East Asia where CO2 concentrations in the upper atmosphere display relatively large variations due to strong updrafts.

scholarly journals Hot-band absorption of indocyanine green for advanced anti-stokes fluorescence bioimaging

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Jing Zhou ◽  
Xiaoxiao Fan ◽  
Di Wu ◽  
Jie Liu ◽  
Yuhuang Zhang ◽  
...  
Keyword(s):  
Blood Vessel ◽  
Indocyanine Green ◽  
Imaging Method ◽  
Urinary System ◽  
Excitation Light ◽  
Cw Laser ◽  
Band Absorption ◽  
Hot Band ◽  
Anti Stokes ◽  
Multi Mode

AbstractBright anti-Stokes fluorescence (ASF) in the first near-infrared spectral region (NIR-I, 800 nm–900 nm) under the excitation of a 915 nm continuous wave (CW) laser, is observed in Indocyanine Green (ICG), a dye approved by the Food and Drug Administration for clinical use. The dependence of fluorescence intensity on excitation light power and temperature, together with fluorescence lifetime measurement, establish this ASF to be originated from absorption from a thermally excited vibrational level (hot-band absorption), as shown in our experiments, which is stronger than the upconversion fluorescence from widely-used rare-earth ion doped nanoparticles. To test the utility of this ASF NIR-I probe for advanced bioimaging, we successively apply it for biothermal sensing, cerebral blood vessel tomography and blood stream velocimetry. Moreover, in combination with L1057 nanoparticles, which absorb the ASF of ICG and emit beyond 1100 nm, these two probes generate multi-mode images in two fluorescent channels under the excitation of a single 915 nm CW laser. One channel is used to monitor two overlapping organs, urinary system & blood vessel of a live mouse, while the other shows urinary system only. Using in intraoperative real-time monitoring, such multi-mode imaging method can be beneficial for visual guiding in anatomy of the urinary system to avoid any accidental injury to the surrounding blood vessels during surgery.

Sign in / Sign up

Export Citation Format

Share Document