Limits...
Applicability of thin film phase plates in biological electron microscopy

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.


(a) modulus of the Fourier transform of an image (shown in Fig. 4a) taken with a 1 μm hole Zernike phase plate, defocus 11.3 μm. (b) rotational average of (a), the cutoff due to phase plate hole size is indicated by a green arrow. (c) modulus of the Fourier transform of an image taken with a 0.3 μm hole Zernike phase plate, defocus 70.5 μm. (d) rotational average of (c).
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC5036645&req=5

f3-2_35: (a) modulus of the Fourier transform of an image (shown in Fig. 4a) taken with a 1 μm hole Zernike phase plate, defocus 11.3 μm. (b) rotational average of (a), the cutoff due to phase plate hole size is indicated by a green arrow. (c) modulus of the Fourier transform of an image taken with a 0.3 μm hole Zernike phase plate, defocus 70.5 μm. (d) rotational average of (c).

Mentions: In the first ZPC-TEM trials phase plates with 1 μm diameter central hole were used2,3. After many experiments and accumulating experience we are currently employing 0.3 μm hole phase plates. In Figs. 3a, c are shown experimental pCTFs taken with 1 μm and 0.3 μm phase plates respectively. The low cutoff frequency (indicated by green arrows in Figs. 3b, d) is improved from 20 nm to 50 nm object periodicity.


Applicability of thin film phase plates in biological electron microscopy
(a) modulus of the Fourier transform of an image (shown in Fig. 4a) taken with a 1 μm hole Zernike phase plate, defocus 11.3 μm. (b) rotational average of (a), the cutoff due to phase plate hole size is indicated by a green arrow. (c) modulus of the Fourier transform of an image taken with a 0.3 μm hole Zernike phase plate, defocus 70.5 μm. (d) rotational average of (c).
© Copyright Policy
Related In: Results  -  Collection

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

f3-2_35: (a) modulus of the Fourier transform of an image (shown in Fig. 4a) taken with a 1 μm hole Zernike phase plate, defocus 11.3 μm. (b) rotational average of (a), the cutoff due to phase plate hole size is indicated by a green arrow. (c) modulus of the Fourier transform of an image taken with a 0.3 μm hole Zernike phase plate, defocus 70.5 μm. (d) rotational average of (c).
Mentions: In the first ZPC-TEM trials phase plates with 1 μm diameter central hole were used2,3. After many experiments and accumulating experience we are currently employing 0.3 μm hole phase plates. In Figs. 3a, c are shown experimental pCTFs taken with 1 μm and 0.3 μm phase plates respectively. The low cutoff frequency (indicated by green arrows in Figs. 3b, d) is improved from 20 nm to 50 nm object 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.