Properties of All-Dielectric Interference Filters II Filters in Parallel Beams of Light Incident Obliquely and in Convergent Beams

Lissberger, P.H.; Wilcock, W. L.

doi:10.1364/josa.49.000126

Cited by 75 publications

(18 citation statements)

References 5 publications

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“…Lissberger and Wilcock, 1959). For incidence angles θ below ∼20 • , the central wavelength λ c of the transmittance window can be approximated by the expression…”

Section: The Filter Illumination Anglementioning

confidence: 99%

Theoretical description of functionality, applications, and limitations of SO<sub>2</sub> cameras for the remote sensing of volcanic plumes

et al. 2010

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Abstract. The SO 2 camera is a novel device for the remote sensing of volcanic emissions using solar radiation scattered in the atmosphere as a light source for the measurements. The method is based on measuring the ultra-violet absorption of SO 2 in a narrow wavelength window around 310 nm by employing a band-pass interference filter and a 2 dimensional UV-sensitive CCD detector. The effect of aerosol scattering can in part be compensated by additionally measuring the incident radiation around 325 nm, where the absorption of SO 2 is about 30 times weaker, thus rendering the method applicable to optically thin plumes. For plumes with high aerosol optical densities, collocation of an additional moderate resolution spectrometer is desirable to enable a correction of radiative transfer effects. The ability to deliver spatially resolved images of volcanic SO 2 distributions at a frame rate on the order of 1 Hz makes the SO 2 camera a very promising technique for volcanic monitoring and for studying the dynamics of volcanic plumes in the atmosphere.This study gives a theoretical basis for the pertinent aspects of working with SO 2 camera systems, including the measurement principle, instrument design, data evaluation and technical applicability. Several issues are identified that influence camera calibration and performance. For one, changes in the solar zenith angle lead to a variable light path length in the stratospheric ozone layer and therefore change the spectral distribution of scattered solar radiation incident at the Earth's surface. The varying spectral illumination causes a shift in the calibration of the SO 2 camera's results. Secondly, the lack of spectral resolution inherent in the measurement technique leads to a non-linear relationshipCorrespondence to: C. Kern (ckern@iup.uni-heidelberg.de) between measured weighted average optical density and the SO 2 column density. Thirdly, as is the case with all remote sensing techniques that use scattered solar radiation as a light source, the radiative transfer between the sun and the instrument is variable, with both "radiative dilution" as well as multiple scattering occurring. These effects can lead to both, over or underestimation of the SO 2 column density by more than an order of magnitude. As the accurate assessment of volcanic emissions depends on our ability to correct for these issues, recommendations for correcting the individual effects during data analysis are given.Aside from the above mentioned intrinsic effects, the particular technical design of the SO 2 camera can also greatly influence its performance, depending on the setup chosen. A general description of an instrument setup is given, and the advantages and disadvantages of certain specific instrument designs are discussed. Finally, several measurement examples are shown and possibilities to combine SO 2 camera measurements with other remote sensing techniques are explored.

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“…Lissberger and Wilcock, 1959). For incidence angles θ below ∼20 • , the central wavelength λ c of the transmittance window can be approximated by the expression…”

Section: The Filter Illumination Anglementioning

confidence: 99%

Theoretical description of functionality, applications, and limitations of SO<sub>2</sub> cameras for the remote sensing of volcanic plumes

et al. 2010

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“…However, the cutoff of the shortpass interference filter shifts to a shorter wavelength for light that hits the filter at an angle less than 90 deg. 30 As a result, each filtered cyan LED produces a spot that is bright in the center and dim around the edges. This vignetting effect is smaller during royal blue excitation because the royal blue LED output (450 nm peak, 24 nm half-width) is further from the shortpass cutoff.…”

Section: Motion Artifact and Ratiometrymentioning

confidence: 99%

Simultaneous optical mapping of transmembrane potential and wall motion in isolated, perfused whole hearts

et al. 2011

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Abstract. Optical mapping of cardiac propagation has traditionally been hampered by motion artifact, chiefly due to changes in photodetector-to-tissue registration as the heart moves. We have developed an optical mapping technique to simultaneously record electrical waves and mechanical contraction in isolated hearts. This allows removal of motion artifact from transmembrane potential (V m ) recordings without the use of electromechanical uncoupling agents and allows the interplay of electrical and mechanical events to be studied at the whole organ level. Hearts are stained with the voltage-sensitive dye di-4-ANEPPS and ring-shaped markers are attached to the epicardium. Fluorescence, elicited on alternate frames by 450 and 505 nm light-emitting diodes, is recorded at 700 frames/ per second by a camera fitted with a 605 ± 25 nm emission filter. Marker positions are tracked in software. A signal, consisting of the temporally interlaced 450 and 505 nm fluorescence, is collected from the pixels enclosed by each moving ring. After deinterlacing, the 505 nm signal consists of V m with motion artifact, while the 450 nm signal is minimally voltage-sensitive and contains primarily artifacts. The ratio of the two signals estimates V m . Deformation of the tissue enclosed by each set of 3 rings is quantified using homogeneous finite strain. C 2011 Society of Photo-Optical Instrumentation Engineers (SPIE).

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“…For non-normal incidence, the transmission characteristics of multilayer bandpass filters are sensitive to the angle of incidence as well as to the thickness and refractive index of the layers [11]. Comprehensive reviews on tilted bandpass filters were studied [5,6], all are modeled in the angular sensitivity of the filter properties according to the monolayer approximation of Pidgeon and Smith up to 15 0 [12].…”

Section: Fig 1 Construction Of Fabry-perot Interference Filter (Singmentioning

confidence: 99%

Design of polarization insensitive narrow bandpass filter

Al-Dahan¹,

Nazar

Rashid

2009

J Opt

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An infrared narrow bandpass filter of single half-wave cavity was designed at non-normal incidence of radiation illuminated by collimated energy within the spectral region (812μm). The change in the spectral characteristic of the filter was studied with the aid of characteristic matrix theory. Further more, needle optimization method was used to provide the best conformance to desire spectral characteristic at the operating conditions of an infrared system, thus, polarization insensitive narrow bandpass was achieved.

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Properties of All-Dielectric Interference Filters II Filters in Parallel Beams of Light Incident Obliquely and in Convergent Beams

Cited by 75 publications

References 5 publications

Theoretical description of functionality, applications, and limitations of SO<sub>2</sub> cameras for the remote sensing of volcanic plumes

Theoretical description of functionality, applications, and limitations of SO<sub>2</sub> cameras for the remote sensing of volcanic plumes

Simultaneous optical mapping of transmembrane potential and wall motion in isolated, perfused whole hearts

Design of polarization insensitive narrow bandpass filter

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Properties of All-Dielectric Interference Filters II Filters in Parallel Beams of Light Incident Obliquely and in Convergent Beams

Cited by 75 publications

References 5 publications

Theoretical description of functionality, applications, and limitations of SO&lt;sub&gt;2&lt;/sub&gt; cameras for the remote sensing of volcanic plumes

Theoretical description of functionality, applications, and limitations of SO&lt;sub&gt;2&lt;/sub&gt; cameras for the remote sensing of volcanic plumes

Simultaneous optical mapping of transmembrane potential and wall motion in isolated, perfused whole hearts

Design of polarization insensitive narrow bandpass filter

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Theoretical description of functionality, applications, and limitations of SO<sub>2</sub> cameras for the remote sensing of volcanic plumes

Theoretical description of functionality, applications, and limitations of SO<sub>2</sub> cameras for the remote sensing of volcanic plumes