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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.


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Phase CTF maps of (a) conventional TEM and (b) Zernike phase contrast TEM.
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f2-2_35: Phase CTF maps of (a) conventional TEM and (b) Zernike phase contrast TEM.

Mentions: Fig. 2a shows a simulated conventional pCTF in what we would like to call a “CTF map”. The plot represents the phase information transfer as a function of spatial frequency and defocus. Effects of energy spread and defocus are included in this simulation resulting in damping of the pCTF at high spatial frequencies with increasing of the defocus. The grayscale is linear and adjusted with black corresponding to 0 and white corresponding to 1. The axes are in logarithmic scale making the data easy to interpret. The scale of the right vertical axis is reciprocal to the spatial frequency. It represents characteristic object size or periodicity.


Applicability of thin film phase plates in biological electron microscopy
Phase CTF maps of (a) conventional TEM and (b) Zernike phase contrast TEM.
© Copyright Policy
Related In: Results  -  Collection

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

f2-2_35: Phase CTF maps of (a) conventional TEM and (b) Zernike phase contrast TEM.
Mentions: Fig. 2a shows a simulated conventional pCTF in what we would like to call a “CTF map”. The plot represents the phase information transfer as a function of spatial frequency and defocus. Effects of energy spread and defocus are included in this simulation resulting in damping of the pCTF at high spatial frequencies with increasing of the defocus. The grayscale is linear and adjusted with black corresponding to 0 and white corresponding to 1. The axes are in logarithmic scale making the data easy to interpret. The scale of the right vertical axis is reciprocal to the spatial frequency. It represents characteristic object size or periodicity.

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.


Related in: MedlinePlus