Optical Treatment of Migraines Using the Avulux™ Optical Filter in the Form of Spectacle Lenses.

1969 ◽

Vol 27 ◽

pp. 170-171

Author(s):

E. Zeitler ◽

M. G. R. Thomson

Keyword(s):

Small Volume ◽

Volume Element ◽

Optical Processing ◽

Image Construction ◽

Object Interaction ◽

Transmission Electron ◽

Scanning Transmission ◽

Optical Treatment ◽

Electron Microscopes ◽

Intensity Contrast

In the formation of an image each small volume element of the object is correlated to an areal element in the image. The structure or detail of the object is represented by changes in intensity from element to element, and this variation of intensity (contrast) is determined by the interaction of the electrons with the specimen, and by the optical processing of the information-carrying electrons. Both conventional and scanning transmission electron microscopes form images which may be considered in this way, but the mechanism of image construction is very different in the two cases. Although the electron-object interaction is the same, the optical treatment differs.

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Chromatic aberration and low-voltage SEM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100127293 ◽

1987 ◽

Vol 45 ◽

pp. 546-547

Author(s):

Zhifeng Shao ◽

A.V. Crewe

Keyword(s):

Electron Energy ◽

Low Voltage ◽

Spherical Aberration ◽

Chromatic Aberration ◽

Primary Electron ◽

Probe Size ◽

Non Local ◽

Optical Treatment ◽

Electron Microscopes ◽

Scanning Electron Microscopes

For scanning electron microscopes, it is plausible that by lowering the primary electron energy, one can decrease the volume of interaction and improve resolution. As shown by Crewe /1/, at V0 =5kV a 10Å resolution (including non-local effects) is possible. To achieve this, we would need a probe size about 5Å. However, at low voltages, the chromatic aberration becomes the major concern even for field emission sources. In this case, δV/V = 0.1 V/5kV = 2x10-5. As a rough estimate, it has been shown that /2/ the chromatic aberration δC should be less than ⅓ of δ0 the probe size determined by diffraction and spherical aberration in order to neglect its effect. But this did not take into account the distribution of electron energy. We will show that by using a wave optical treatment, the tolerance on the chromatic aberration is much larger than we expected.

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Performance and Reliability of a MEMS-based tunable optical filter operating in the 1565 nm-1525 nm wavelength range

MRS Proceedings ◽

10.1557/proc-722-k6.3 ◽

2002 ◽

Vol 722 ◽

Author(s):

T. S. Sriram ◽

B. Strauss ◽

S. Pappas ◽

A. Baliga ◽

A. Jean ◽

...

Keyword(s):

Silicon Nitride ◽

Line Width ◽

Insertion Loss ◽

Optical Filter ◽

Single Mode ◽

Single Mode Fiber ◽

Reliability Testing ◽

Silicon Nitride Membrane ◽

Tunable Optical Filter ◽

Extensive Performance

AbstractThis paper describes the results of extensive performance and reliability characterization of a silicon-based surface micro-machined tunable optical filter. The device comprises a high-finesse Fabry-Perot etalon with one flat and one curved dielectric mirror. The curved mirror is mounted on an electrostatically actuated silicon nitride membrane tethered to the substrate using silicon nitride posts. A voltage applied to the membrane allows the device to be tuned by adjusting the length of the cavity. The device is coupled optically to an input and an output single mode fiber inside a hermetic package. Extensive performance characterization (over operating temperature range) was performed on the packaged device. Parameters characterized included tuning characteristics, insertion loss, filter line-width and side mode suppression ratio. Reliability testing was performed by subjecting the MEMS structure to a very large number of actuations at an elevated temperature both inside the package and on a test board. The MEMS structure was found to be extremely robust, running trillions of actuations without failures. Package level reliability testing conforming to Telcordia standards indicated that key device parameters including insertion loss, filter line-width and tuning characteristics did not change measurably over the duration of the test.

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All-optical logic gates based on an SOA and an optical filter

31st European Conference on Optical Communications (ECOC 2005) ◽

10.1049/cp:20050456 ◽

2005 ◽

Cited By ~ 1

Author(s):

Z. Li

Keyword(s):

Optical Filter ◽

Logic Gates ◽

Optical Logic ◽

Optical Logic Gates ◽

All Optical

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Optical Filter Net: A Spectral-Aware RGB Camera Framework for Effective Green Pepper Segmentation

IEEE Access ◽

10.1109/access.2021.3091305 ◽

2021 ◽

pp. 1-1

Author(s):

Jun Yu ◽

Toru Kurihara ◽

Shu Zhan

Keyword(s):

Optical Filter ◽

Green Pepper

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Asymmetrical clipping optical filter bank multi-carrier modulation scheme

Optical and Quantum Electronics ◽

10.1007/s11082-021-02867-2 ◽

2021 ◽

Vol 53 (5) ◽

Author(s):

Asmaa Ibrahim ◽

Josep Prat ◽

Tawfik Ismail

Keyword(s):

Filter Bank ◽

Optical Filter ◽

Modulation Scheme

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A Switchable Optical Filter between Band-stop and Band-pass Responses

2020 Opto-Electronics and Communications Conference (OECC) ◽

10.1109/oecc48412.2020.9273709 ◽

2020 ◽

Author(s):

Weijun Jiang ◽

Lu Xu ◽

Xiaolong Liu ◽

Yu Yu ◽

Yuan Yu ◽

...

Keyword(s):

Optical Filter ◽

Band Pass

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Analysis of Dielectric Waveguide Grating and Fabry–Perot Modes in Elastic Grating in Optical Detection of Ultrasound

Sensors ◽

10.3390/s21124081 ◽

2021 ◽

Vol 21 (12) ◽

pp. 4081

Author(s):

Suejit Pechprasarn ◽

Chayanisa Sukkasem ◽

Phitsini Suvarnaphaet

Keyword(s):

Optical Properties ◽

Dielectric Waveguide ◽

Figure Of Merit ◽

Pressure Range ◽

Optical Filter ◽

Grating Period ◽

Wave Mode ◽

Waveguide Grating ◽

Fabry Perot ◽

Optical Grating

In our previous work, we have demonstrated that dielectric elastic grating can support Fabry–Perot modes and provide embedded optical interferometry to measure ultrasonic pressure. The Fabry–Perot modes inside the grating provide an enhancement in sensitivity and figure of merit compared to thin film-based Fabry–Perot structures. Here, in this paper, we propose a theoretical framework to explain that the elastic grating also supports dielectric waveguide grating mode, in which optical grating parameters control the excitation of the two modes. The optical properties of the two modes, including coupling conditions and loss mechanisms, are discussed. The proposed grating has the grating period in micron scale, which is shorter than the wavelength of the incident ultrasound leading to an ultrasonic scattering. The gap regions in the grating allow the elastic grating thickness to be compressed by the incident ultrasound and coupled to a surface acoustic wave mode. The thickness compression can be measured using an embedded interferometer through one of the optical guided modes. The dielectric waveguide grating is a narrow bandpass optical filter enabling an ultrasensitive mode to sense changes in optical displacement. This enhancement in mechanical and optical properties gives rise to a broader detectable pressure range and figure of merit in ultrasonic detection; the detectable pressure range and figure of merit can be enhanced by 2.7 times and 23 times, respectively, compared to conventional Fabry–Perot structures.

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