For short wavelength imaging systems,surface scattering effects is one of important factors degrading imaging performance. Study of non-intuitive surface scatter effects resulting from practical optical fabrication tolerances is a necessary work for optical performance evaluation of high resolution short wavelength imaging systems. In this paper, Soft X-ray optical scattering distribution is measured by a soft X-ray reflectometer installed by my lab, for different sample mirrors、wavelength and grazing angle. Then aim at space solar telescope, combining these scattered light distributions, and surface scattering numerical model of grazing incidence imaging system, PSF and encircled energy of optical system of space solar telescope are computed. We can conclude that surface scattering severely degrade imaging performance of grazing incidence systems through analysis and computation.
Optical fiber sensor technology is one of the main contents of modern information technology, which has a very important position in modern science and technology. Fiber optic sensor experiment can improve students' enthusiasm and broaden their horizons in college physics experiment. In this paper the main structure and working principle of fiberoptical sensor with intensity compensation model are introduced. And thus fiber-optical sensor with intensity compensation model is applied to measure micro displacement of Young's modulus measurement experiment and metal linear expansion coefficient measurement experiment in the college physics experiment. Results indicate that the measurement accuracy of micro displacement is higher than that of the traditional methods using fiber-optical sensor with intensity compensation model. Meanwhile this measurement method makes the students understand on the optical fiber, sensor and nature of micro displacement measurement method and makes each experiment strengthen relationship and compatibility, which provides a new idea for the reform of experimental teaching.
The Generalzed Lorenz-Mie theory (GLMT), which describes the interaction between spherical particles and laser
pulses, is firstly introduced in this paper. Then time structures of the scattering properties for ultra-short laser pulses by air bubbles in the sea water are studied, including the scattering intensity, scattering efficiency factor and extinction efficiency factor, and influences of the bubble size, pulse duration and scattering angle on time structures of a scattered pulse for a bubble are discussed. Finally, transient properties of a scattered bubble for a bubble are compared with those of suspended particles in the sea water.
The optical performance is severely degraded by surface scattering effect, especially for short wavelength imaging
systems. Surface scattering effect is one of important factors degrading imaging performance. Study of non-intuitive
surface scattering effect resulted from practical optical fabrication tolerances is a necessary work for optical performance evaluation of high resolution imaging systems. In this paper, a surface scattering numerical model of grazing incidence imaging systems is discussed. Then Soft X-ray optical scattering distribution is measured by soft X-ray reflectometer at different conditions. PSF (point spread function) is computed by experimental data of sample, and compared with PSF analysized by scattering LSI model. It is indicated that we can detect short wavelength optical scattering Phenomena through soft X-ray grazing incidence optical scattering experimentation we did.
The Generalized Lorenz-Mie theory(GLMT), which describes the interaction between spherical particles and laser pulses,
is firstly introduced in this paper. Then scattering properties of ultrashort laser pulses by air bubbles in the sea water are
studied, including the scattering efficiency factor, extinction efficiency factor, phase function and degree of polarization,
and influences of the bubble size, pulse duration and scattering angle on pulse scattering properties are discussed. Finally,
pulse scattering properties of bubbles are compared with those of suspended particles in the sea water. The results show
that laser pulses have the smoothing effect, which strengthens with decrease of the pulse duration, but have no influences
on the critical angle scattering and Brewster angle scattering. So they could be measured to distinguish between air
bubbles and suspended particles and thus to detect air bubbles. This will have certain significances on pulsed laser
detection for wake bubbles. The results also show that small bubbles could enhance the backscattering of the sea water,
which is advantageous for pulsed laser detection for wake bubbles.
KEYWORDS: Scattering, Space telescopes, Light scattering, Solar telescopes, Imaging systems, Grazing incidence, X-rays, Mirrors, Reflectometry, Solar energy
Aperture diffraction ageometric aberrations asurface scatter and other errors -setting errors Aenvironmental errors- are
several influencing factors on imaging performance of optical system. Especially for short wavelength imaging systems,
Surface scattering effects is one of mainly influencing factors which is severely degraded imaging performance. It is
necessary that study surface scattering phenomenon to development of short wavelength optics. In this paper, aim at
space solar telescope, effect of surface scattering on imaging performance of the grazing incidence systems is evaluated.
By combining these scattered light distributions of super-smooth surfaces measured by a soft X-ray reflectometer, and
surface scattering numerical model of grazing incidence imaging system, PSF and encircled energy of optical system of
space solar telescope are computed. We can conclude that surface scattering severely degrade imaging performance of
grazing incidence systems through analysis and computation.a
KEYWORDS: Scattering, Light scattering, Laser scattering, Interference (communication), Fourier transforms, Signal processing, Autoregressive models, Mie scattering, Signal detection, Signal to noise ratio
For the detection of the bubble-laser-scattering property, it is the key to improve the signal to noise ratio. The various
noises in the bubble-laser-scattering signal, the background light, power frequency of 50Hz, radio frequency noise and
inherent noise within the electronic system, are analyzed in detailed. Two frequency-domain methods used to process the
bubble scattering signal, the Fourier transform and the power spectral estimation, are focused on. These two methods can
reduce the noise, isolate the DC component and eliminate the impact of the power frequency of 50Hz, thus the pulse of
bubble laser scattering could be detected. The physical meaning for the power spectral estimation is much clearer than
that of the Fourier transform. The power spectrum curve obtained by using the Yule-Walker AR (regression model)
method is much smoother and its frequency resolution is higher than the other methods. The results show that the Yule-
Walker AR spectrum estimation is the most reasonable and most effective method.
The bubble backscattering intensity between 140 and 160 degree is achieved utilizing bistatic method, and the bubble
scattering signal is detected, analyzed and processed. The photo multiplier tube is used to detect the weak signal.
Threshold detection distinguishes between the bubble backscattering and water backscattering. Bubble scattering pulses
are stationary random signals and have statistic properties. So the sample average for an enough long time may be as the
scattering intensity at a certain angle. Experimental results have the same trend as the theoretical results. The
experimental research on the bubble backscattering properties is importance to the ocean sensing and wake homing.
Mie theory is used to study the influence of organic film coatings for bubbles on optical scattering properties of ship wakes. The influence of organic film coatings on the normalized volume scattering function of single bubble is researched. Based on the fractal data of ship wakes, analysis and comparison are made on the scattering properties of clean and coated bubbles, including the normalized volume scattering function, scattering coefficient, backscattering coefficient and backscattering ratio. Organic film coatings have little influence on the critical angle scattering. Contributions of the organic film coatings to the scattering properties of ship wakes relates to the thickness and refractive index of them, in addition, the normalized volume scattering function also relates to the scattering angle. Scattering properties of ship wakes are of importance to wake homing and optical remote sensing of ocean.
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