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Applicability of thin film phase plates in biological electron microscopy

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ABSTRACT

Presented is an evaluation of phase contrast techniques in transmission electron microscopy. The traditional defocus phase contrast is compared to two recently developed phase plate techniques. One is the Zernike phase contrast transmission electron microscope, the other is the Hilbert differential contrast thransmission electron microscope. The imaging characteristics of each technique are discussed. Phase plate techniques provide improved contrast for ice-embedded biological samples which are a challenge for the conventional defocus phase contrast. The flat spectral response of the Zernike and Hilbert modes extends towards the low frequencies which are severely suppressed in the conventional defocus mode. Target applications for each of the phase contrast techniques are discussed based on the specifics of image formation and spectral transfer.

No MeSH data available.


Illustration of HDC-TEM image demodulation. (a) HDC-TEM image of ice-embedded rotaviruses (Taniguchi, K., Danev, R., Usuda, N. and Nagayama, K., unpublished data). (b) numerically demodulated image.
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f7-2_35: Illustration of HDC-TEM image demodulation. (a) HDC-TEM image of ice-embedded rotaviruses (Taniguchi, K., Danev, R., Usuda, N. and Nagayama, K., unpublished data). (b) numerically demodulated image.

Mentions: It was shown in previous reports7 that it is possible to numerically demodulate the HDC-TEM image and remove the topographic appearance. Figs. 7a, b show an example of such demodulation. In the ideal case of central beam infinitely close to the phase plate edge the result will be an image with ideal ZPC-TEM like pCTF modulation. However due to the finite beam to edge distance the demodulated image still has some anisotropic appearance. There are more low frequencies in direction perpendicular to the phase plate edge than in other directions. This is due to the fact that in that direction the phase plate edge is closest to the k-space origin.


Applicability of thin film phase plates in biological electron microscopy
Illustration of HDC-TEM image demodulation. (a) HDC-TEM image of ice-embedded rotaviruses (Taniguchi, K., Danev, R., Usuda, N. and Nagayama, K., unpublished data). (b) numerically demodulated image.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC5036645&req=5

f7-2_35: Illustration of HDC-TEM image demodulation. (a) HDC-TEM image of ice-embedded rotaviruses (Taniguchi, K., Danev, R., Usuda, N. and Nagayama, K., unpublished data). (b) numerically demodulated image.
Mentions: It was shown in previous reports7 that it is possible to numerically demodulate the HDC-TEM image and remove the topographic appearance. Figs. 7a, b show an example of such demodulation. In the ideal case of central beam infinitely close to the phase plate edge the result will be an image with ideal ZPC-TEM like pCTF modulation. However due to the finite beam to edge distance the demodulated image still has some anisotropic appearance. There are more low frequencies in direction perpendicular to the phase plate edge than in other directions. This is due to the fact that in that direction the phase plate edge is closest to the k-space origin.

View Article: PubMed Central - PubMed

ABSTRACT

Presented is an evaluation of phase contrast techniques in transmission electron microscopy. The traditional defocus phase contrast is compared to two recently developed phase plate techniques. One is the Zernike phase contrast transmission electron microscope, the other is the Hilbert differential contrast thransmission electron microscope. The imaging characteristics of each technique are discussed. Phase plate techniques provide improved contrast for ice-embedded biological samples which are a challenge for the conventional defocus phase contrast. The flat spectral response of the Zernike and Hilbert modes extends towards the low frequencies which are severely suppressed in the conventional defocus mode. Target applications for each of the phase contrast techniques are discussed based on the specifics of image formation and spectral transfer.

No MeSH data available.