Digital DIC
Iatia's QPI generates quantitative phase data based on relative changes in the optical thickness of a sample. This phase data can be used to digitally generate analogues of conventional optical phase contrast systems such as Differential Interference contrast (DIC).
QPI's digitally generated phase contrast images provide additional flexibility and functionality without the inherent limitations of optical systems:
- Non-polarized illumination
- Full analog of optical controls such as 360o rotation of DIC's Wollaston Prism and transmission plate adjustments in optical phase contrast
- Insensitive to birefringent plastic cultureware
- Returns phase and amplitude/absorption information independently allowing for selective visualization of phase information without amplitude/absorption information
- Generate phase contrast images at all magnifications without the need for additional optics or changes to the optical path
QPI also generates other phase contrast images such as "phase" (contrast) and Hoffman Modulation Contrast.
Fossilized leaf
This fossilized leaf sample serves to illustrate the features of QPI's phase contrast visualization capabilities with the brightfield image of the sample exhibiting poor cellular discrimination as well as obscuring amplitude/absorption information such as stains (in this case, dirt and dust)1,2.
Brightfield
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QPI phase map
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Optical DIC
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QPI DIC
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As shown in the images above, the QPI phase map represents calculations of changes in optical thickness across the sample in grayscale. QPI can then combine this pure phase map with amplitude/absorption information (brightfield image) to produce DIC's characteristic shadow relief representation of phase changes. As shown above, the QPI DIC image correlates well with the optical DIC image.
Unique to QPI is the ability to separate phase from amplitude/absorption information to produce an amplitude/absorption free DIC image, shown on the right. In this sample, amplitude/absorption information such as stains, dirt and dust was removed from the DIC image to reveal the underlying cell structure.
References
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Optical Phase Microscopy: Quantitative Imaging and Conventional Phase Analogs
BE Allman, ML von Bibra, CJ Bellair, A Kabbara, E Barone-Nugent, AP Gaeth, LM Delbridge and KA Nugent, Microscopy and Microanalysis, 87, 13-15 (UK Ed.), 25, 5-7 (Asia/Pacific Ed.) (2002). -
Quantitative Phase-Amplitude Imaging I: Optical Microscopy
ED Barone-Nugent, A Barty and KA Nugent, Journal of Microscopy, 206, 194-203, (2002).