Ultraviolet Sensor Based on a Silica Optical Microresonator

2014 ◽  
Vol 1698 ◽  
Author(s):  
Simin Mehrabani ◽  
Audrey Harker ◽  
Andrea Armani
Keyword(s):  
Uv Light ◽  
Signal To Noise Ratio ◽  
Whispering Gallery Mode ◽  
Uv Exposure ◽  
High Signal ◽  
Uv Sensor ◽  
Whispering Gallery ◽  
Exposure Levels ◽  
Very High ◽  
Ultraviolet Sensor

ABSTRACTIt is well known that exposure to ultraviolet (UV) light can result in various physical and psychological diseases. Therefore, there is a strong demand for a reliable sensor to monitor UV exposure levels in the physiologically relevant intensity ranges of mW/cm2. Here, we demonstrate a UV sensor based on a silica whispering gallery mode microresonator. This UV sensor works over physiologically relevant intensity ranges with linear performance both in the forward and backward operating directions, with very high signal-to-noise ratio that can be utilized in monitoring the UV exposure for various applications.

Observations of TiO2 Surfaces Using Totally Reflected X-ray In-plane Diffraction Under UV Irradiation

2002 ◽  
Vol 751 ◽  
Author(s):  
T. Horiuchi ◽  
H. Ochi ◽  
K. Kaisei ◽  
K. Ishida ◽  
K. Matsushige
Keyword(s):  
Uv Irradiation ◽  
Uv Light ◽  
Plane Surface ◽  
Signal To Noise Ratio ◽  
High Surface ◽  
Ultra Violet ◽  
High Signal ◽  
X Ray ◽  
Force Microscopy ◽  
Catalytic Activities

ABSTRACTSurface lattice displacements of titanium dioxide (TiO2: rutile) during ultra-violet (UV) light irradiation have been investigated using a total reflection x-ray diffraction, which provides a high signal to noise ratio (S/N) and superior in-plane surface diffraction. Under the environments in vapors of H2O, CH3OH, C2H5OH and C3H6OH, the photo-catalytic activities of TiO2 (110), (100) and (001) surfaces subject to UV irradiation have been measured. It is found that the diffraction peaks and their full width half maxima (FWHMs) show some peculiarities with respect to the photo-catalytic activities in both surface lattices and adsorbed molecules in vapors. Furthermore, Kelvin force microscopy (KFM) has showed that there exists a very high surface potential, probably due to surface atom displacements induced by UV irradiation. With regard to the origin of the photo-catalytic activities, the induced surface potentials are discussed.

Effects of Very High Neutron Fluence Irradiation on p+n Junction 4H-SiC Diodes

2007 ◽  
Vol 556-557 ◽  
pp. 917-920 ◽  
Author(s):  
Francesco Moscatelli ◽  
Andrea Scorzoni ◽  
Antonella Poggi ◽  
Mara Passini ◽  
Giulio Pizzocchero ◽  
...  
Keyword(s):  
Leakage Current ◽  
Leakage Current Density ◽  
Current Density ◽  
Reverse Bias ◽  
Neutron Fluence ◽  
Signal To Noise Ratio ◽  
Reverse Current ◽  
Low Noise ◽  
High Signal ◽  
Very High

In this work we analyzed the radiation hardness of SiC p+n diodes after very high 1 MeV neutron fluence. The diode structure is based on a p+ emitter ion implanted in n-type epilayer with thickness equal to 5 %m and donor doping ND = 3×1015 cm-3. Before irradiation, the average leakage current density at 100 V reverse bias was of the order of 3 nA/cm2. These devices were irradiated at four different fluence values, logarithmically distributed in the range 1014-1016 (1 MeV) neutrons/cm2. After irradiation the epilayer material became more resistive, as indicated by the reduction of the forward and reverse current density at a given voltage. In particular, after a neutron fluence of 1×1014 n/cm2 the epilayer active doping concentration decreased to 1.5×1015 cm-3. After irradiation at 1016 n/cm2, i.e. the highest fluence value, the average leakage current density at 100 V reverse bias decreased to values of the order of 0.1 nA/cm2. This very low noise even after very high fluence is very important to obtain a high signal to noise ratio even at room temperature.

scholarly journals ACE-FTS observation of a young biomass burning plume: first reported measurements of C<sub>2</sub>H<sub>4</sub>, C<sub>3</sub>H<sub>6</sub>O, H<sub>2</sub>CO and PAN by infrared occultation from space

2007 ◽  
Vol 7 (3) ◽  
pp. 7907-7932 ◽  
Author(s):  
P.-F. Coheur ◽  
H. Herbin ◽  
C. Clerbaux ◽  
D. Hurtmans ◽  
C. Wespes ◽  
...  
Keyword(s):  
Biomass Burning ◽  
Atmospheric Chemistry ◽  
Signal To Noise Ratio ◽  
Source Region ◽  
High Signal ◽  
Upper Troposphere ◽  
Organic Species ◽  
Specific Biomass ◽  
Chemistry Experiment ◽  
Very High

Abstract. In the course of our study of the upper tropospheric composition with the infrared Atmospheric Chemistry Experiment – Fourier Transform Spectrometer (ACE–FTS), we found an occultation sequence that on 8 October 2005, sampled a remarkable plume near the east coast of Tanzania. Model simulations of the CO distribution in the Southern hemisphere are performed for this period and they demonstrate that the emissions for this event originated from a nearby forest fire, after which the plume was transported from the source region to the upper troposphere. Taking advantage of the very high signal-to-noise ratio of the ACE–FTS spectra over a wide wavenumber range (750–4400 cm−1), we present in-depth analyses of the chemical composition of this plume in the middle and upper troposphere, focusing on the measurements of weakly absorbing pollutants. For this specific biomass burning event, we report simultaneous observations of an unprecedented number of organic species. Measurements of C2H4 (ethene), C3H4 (propyne), H2CO (formaldehyde), C3H6O (acetone) and CH3COO2NO2 (peroxyacetylnitrate, abbreviated as PAN) are the first reported detections using infrared occultation spectroscopy from satellites. Based on the lifetime of the emitted species, we discuss the photochemical age of the plume and also report, whenever possible, the enhancement ratios relative to CO.

Optical Whispering-Gallery Mode Phenomenon as a Composite Sensor With Applications to Direct On-Chip Thermal Sensing

2013 ◽  
Author(s):  
Matthew Frenkel ◽  
Marlon Avellan ◽  
Zhixiong Guo
Keyword(s):  
Composite System ◽  
Whispering Gallery Mode ◽  
Quality Factors ◽  
Pressure Sensing ◽  
Whispering Gallery ◽  
Area Of Interest ◽  
Thermal Sensing ◽  
On Chip ◽  
Wgm Resonators ◽  
Very High

Optical Whispering-Gallery Mode (WGM) resonators can be fabricated with very high quality factors allowing for their use as high resolution sensors in a myriad of fields ranging from quantum electro-dynamics (QED) to pressure sensing. In this paper, we focus on integrating WGM as a dynamic temperature measurement device. The WGM sensors are fabricated onto the heating element, instead of acting as an indirect temperature sensor, allowing for direct monitoring of an area of interest. An adaptation to the WGM theoretical model, to include the thermal expansion of the composite system, is discussed and analyzed.

scholarly journals Recent Helioseismological Results from Space: Solar p-mode Oscillations from IPHIR on the PHOBOS Mission

1990 ◽  
Vol 121 ◽  
pp. 279-288
Author(s):  
C. Fröhlich ◽  
T. Toutain ◽  
R.M. Bonnet ◽  
A.V. Bruns ◽  
J.P. Delaboudinière ◽  
...  
Keyword(s):  
Signal To Noise Ratio ◽  
Accurate Determination ◽  
Spectral Irradiance ◽  
High Signal ◽  
Line Shapes ◽  
Solar Spectral Irradiance ◽  
Evaluation Of Data ◽  
Very High ◽  
Better Than

AbstractIPHIR (Interplanetary Helioseismology by IRradiance measurements) is a solar irradiance experiment on the USSR planetary mission PHOBOS to Mars and its satellite Phobos. The experiment was built by an international consortium including PMOD/WRC, LPSP, SSD/ESA, KrAO and CRIP. The sensor is a three channel sunphotometer (SPM) which measures the solar spectral irradiance at 335, 500 and 865 nm with a precision of better than 1 part-per-million (ppm). It is the first experiment dedicated to the investigation of solar oscillations from space. The results presented here are from a first evaluation of data gathered during 160 days of the cruise phase of PHOBOS II, launched on July, 12th 1988. The long uninterrupted observation produces a spectrum of the solar p-mode oscillations in the 5-minute range with a very high signal-to-noise ratio, which allows an accurate determination of frequencies and line shapes of these modes.

Anti-Vibration Sub Allows A Very High Signal-To-Noise Ratio And Improves Borehole Quality

2013 ◽  
Author(s):  
Paul Christian Bates ◽  
Chakib Bouziane ◽  
Denise Nicholl ◽  
Reina Teelken ◽  
Mohammed Zuki Bin Bidi ◽  
...  
Keyword(s):  
Signal To Noise Ratio ◽  
High Signal ◽  
Signal To Noise ◽  
Noise Ratio ◽  
Very High

scholarly journals Deformed microcavities with very high Q-factors and directional farfield emission

2020 ◽  
Vol 238 ◽  
pp. 01006
Author(s):  
Arne Behrens ◽  
Martí Bosch ◽  
Martina Hentschel ◽  
Stefan Sinzinger
Keyword(s):  
Surface Roughness ◽  
State Of The Art ◽  
Whispering Gallery Mode ◽  
Q Factor ◽  
Tapered Fiber ◽  
High Q ◽  
Whispering Gallery ◽  
Q Factors ◽  
Very High

We report the design and optimized fabrication of deformed whispering gallery mode resonators in silica with solely ICP-RIE. This allows us to control the morphology of the resonators more freely and results in low surface roughness. The light was coupled into the resonator using a state of the art tapered fiber approach and we determined the Q-factor in the range of 105

Fabrication of high-performance photodetector based on AlGaN/GaN hetero-field-effect transistors with p-GaN gate

2006 ◽  
Vol 955 ◽  
Author(s):  
Shuichi Miura ◽  
Takahiro Fujii ◽  
Motoaki Iwaya ◽  
Satoshi Kamiyama ◽  
Hiroshi Amano ◽  
...  
Keyword(s):  
Field Effect ◽  
High Performance ◽  
Field Effect Transistor ◽  
Field Effect Transistors ◽  
Uv Light ◽  
Signal To Noise Ratio ◽  
High Signal ◽  
Dark Current Density ◽  
Effect Transistor ◽  
P Type

ABSTRACTAn AlGaN/GaN photo-hetero-field-effect transistor (photo-HFET) with a p-type GaN gate was fabricated and its properties were compared with those of a HFET without a p-type GaN layer. The photo-HFET with a p-GaN gate exhibited a high signal-to-noise ratio of five orders of magnitude and a dark current density of 10 nA/mm at a drain-source bias of 5 V. In contrast, when the photo-HFET was irradiated with 365 nm (490 μW/cm2) UV light, a photocurrent of over 1 mA/mm was achieved. The responsivity of the device was over 1 × 105 A/W.

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