Nonlinear spatial filtering with a dye-doped liquid-crystal cell

Kato, Junichi; Yamaguchi, Ichirou; Tanaka, Hiroshi

doi:10.1364/ol.21.000767

Cited by 47 publications

(12 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The defects are enhanced, but their vicinity is not free of other structures. This can be veri®ed by numerical simulations, when a complex object consisting of rectangular, circular and grating-like structures is examined (see section 6).…”

Section: Self-®ltering Procedures With Optically Addressed Spatial Ligmentioning

confidence: 84%

See 1 more Smart Citation

Spatial self-filtering using photorefractive and liquid crystals

Wagemann

Tiziani

1998

Journal of Modern Optics

View full text Add to dashboard Cite

In a paper by MoÈ bus et al. a method for defect enhancement by spatial self-®ltering using B12SiO20 (BSO) in the Fourier plane of an optical processor was presented. In periodic structures the unwanted sharp peaks in the Fourier plane have to be removed in order to enhance defects. In this paper we describe sub-micron defect detection by self-®ltering with BSO in detail and compare the photorefractive method with a new very promising ®ltering approach using optically addressed spatial light modulators (OASLM). Interesting results especially for chromium-on-glass masks, CCD arrays and memory chips were obtained with a simple set-up. In addition numerical techniques will be examined.

show abstract

Section: Self-®ltering Procedures With Optically Addressed Spatial Ligmentioning

confidence: 84%

“…The ®ltering element is positioned in the second Fourier plane, FP 2 (see ®gure 6). Most experiments depicted below have been performed with ¶ = 633 nm and a 40 £ /0.65 microscope objective.…”

Section: Self-®ltering Procedures With Bso: Experimental Resultsmentioning

confidence: 99%

Spatial self-filtering using photorefractive and liquid crystals

Wagemann

Tiziani

1998

Journal of Modern Optics

View full text Add to dashboard Cite

show abstract

“…While our group demonstrated a self-adaptive all-optical Fourier image processing system using photoinduced dichroic characteristics [22], Korchemskaya's group exploited photoinduced anisotropy for real-time selective image processing [23]. On the other hand, several other groups exploited similar photoinduced polarization rotation properties of azobenzene dye doped liquid crystal and polymer films for spatial filtering [24][25][26]. Simply by placing a polarizer sheet at the Fourier plane, Ferrari et al demonstrated phase visualization and edge enhancement [27].…”

Section: Photoinduced Anisotropy For Medical Image Processingmentioning

confidence: 99%

Optical Fourier techniques for medical image processing and phase contrast imaging

Yelleswarapu

Kothapalli

Rao

2008

Optics Communications

View full text Add to dashboard Cite

This paper briefly reviews the basics of optical Fourier techniques (OFT) and applications for medical image processing as well as phase contrast imaging of live biological specimens. Enhancement of microcalcifications in a mammogram for early diagnosis of breast cancer is the main focus. Various spatial filtering techniques such as conventional 4f filtering using a spatial mask, photoinduced polarization rotation in photosensitive materials, Fourier holography, and nonlinear transmission characteristics of optical materials are discussed for processing mammograms. We also reviewed how the intensity dependent refractive index can be exploited as a phase filter for phase contrast imaging with a coherent source. This novel approach represents a significant advance in phase contrast microscopy.

show abstract

“…Such a configuration extends over at least two focal lengths of both lenses and is of a relatively large size -it could hardly be used in micro-or nano-scale photonic devices. Other, more sophisticated arrangements for spatial filtering based on liquid-crystal cells [2], utilization of thin film interfaces [3], anisotropic media [4], metallic grids [5], possibly including monolithically integrated passive beam shaping elements [6], etc. have not resulted in widespread technological applications.…”

Section: Introductionmentioning

confidence: 99%

Femtosecond direct laser writing of photonic spatial filters in soda–lime glass

Gailevičius¹,

Purlys²,

Maigytė³

et al. 2015

Lith. J. Phys.

View full text Add to dashboard Cite

An experimental study of the efficiency of recently predicted photonic crystal (PhC) based spatial filtering is provided. Photonic structures are fabricated using a direct laser writing technique employing point-by-point modification by tightly focused femtosecond pulses in soda-lime glass. Such PhCs are characterized by using an s-coefficient -a parameter defining PhC filter efficiency. We explore the dependences of filtering efficiency on different laser writing conditions, such as irradiation peak intensity and the polarization of laser beam. In addition, we show that the PhCs can also exhibit even asymmetric shapes of voxels under particular conditions.

show abstract

Nonlinear spatial filtering with a dye-doped liquid-crystal cell

Cited by 47 publications

References 7 publications

Spatial self-filtering using photorefractive and liquid crystals

Spatial self-filtering using photorefractive and liquid crystals

Optical Fourier techniques for medical image processing and phase contrast imaging

Femtosecond direct laser writing of photonic spatial filters in soda–lime glass

Contact Info

Product

Resources

About