Nomarski differential interference contrast

Nomarski differential interference contrast microscopy is an alternative to phase contrast microscopy which gives an almost three... 

To understand the release mechanism, cryomicrotomy was used to slice 10 m-thick sections throughout the matrices. Viewed under an optical microscope, polymer films cast without proteins appeared as nonporous sheets. Matrices cast with proteins and sectioned prior to release displayed areas of either polymer or protein. Matrices initially cast with proteins and released to exhaustion (e.g., greater than 5 months) appeared as porous films. Pores with diameters as large as 100 /xm, the size of the protein particles, were observed. The structures visualized were also confirmed by Nomarski (differential interference contrast microscopy). It appeared that although pure polymer films were impermeable to macromolecules (2), molecules incorporated in the matrix dissolved once water penetrated the matrix and were then able to diffuse to the surface through pores created as the particles of molecules dissolved. Scanning electron microscopy showed that the pores were interconnected (7). 

The Nomarski differential interference contrast technique accentuates changes in specimen thickness and refractive index in transmission without giving the haloes round fine features that distract from the usefulness of the phase-contrast technique. In reflection, images are obtained that strongly accentuate the topographical features present. 

Nomarski Differential Interference Contrast (DIC). In 1955 the physicist George Nomarski simplified the two-beam interference microscope in a way that it became available for routine microscopy [11 (Fig, 6), DIC uses modified Wollaston prisms (Fig. 6B). lying outside the focal... 

W. Lang Nomarski Differential Interference Contrast Microscopy. Zeiss Inf. 16 (1968) no. 70, 114-120. 

When sections were stained with Sudan IV, some darker areas were apparent. In Fig. 15, in addition to staining preferentially for fat, Nomarski differential interference-contrast microscopy was used. The darkest areas contain lipid and appear raised... 

Fig. 15. Aortic lesion stained to visualize lipid deposits and viewed with Nomarski differential interference-contrast optics (Sudan IV)...

Fig. 2. Differential interference contrast (Nomarski) microscope, showing exaggerated light path (12).

Nomarski microscopy is an examination mode using differential interference contrast (DIC). The images that DIC produces are deceptively three-dimensional with apparent shadows and a relief-like appearance. Nomarski microscopy also uses polarized light with the polarizer and the analyzer arranged as in the polarized light mode. In addition, double quartz prisms ( Wollaston prisms or DIC prisms) are used to split polarized light and generate a phase difference. 

Hie most important optical technique for examining semiconductor wafer surfaces is the differential interference contrast microscopy method of Nomarski (N-DIC). First described in 1952, DIG... 

Another system for examination of low-contrast objects such as living cells is the Nomarski or differential interference contrast system. It is also particularly useful for materials that cannot be stained satisfactorily for other reasons, such as very thin sections that take up too little stain. This system employs polarizing filters and quartz prisms instead of the annular diaphragm and phase plates used in phase contrast. This eliminates the halo effect seen in phase contrast, rendering sharply defined images with good contrast, having a characteristically (pseudo) three-dimensional appearance. It is rather less suited to routine work than phase contrast however, and is considerably more expensive. 

Nomarski microscopy Differential interference contrast microscopy utilizes differences in refractive index to visuahze structures producing a nearly three-dimensional image. 

Patches are normally obtained under an inverted microscope. The magnification will depend on the size of the cells that are going to be studied. Illumination is phase contrast or differential interference contrast (Nomarski) in order to have a clear image of cells, taking into account that they are living cells without any dye. The illumination power supply of the microscope has to be localized far from the set-up, especially when it is an a.c. power supply. 

However, the most widely used type of interference microscopy is that giving Differential Interference Contrast (DIC), widely known as Nomarski contrast. 

Another technique for crystallinity analysis is the measurement of pole figures. It is widely applied for thin films, LPE films, melt-processed polycrystalline samples with a noticeable texture (Goyal et al. 1993). In fig. 33, a good crystallinity of the Y123 LPE film is evidently obtained due to a specific growth mechanism, mentioned above (sect. 5.4), despite the large misfit between the film and the MgO substrate. Differential interference contrast (DIM or Nomarski) microscopy can be successfully applied to observe misorientation on flat ( mirror-like ) surfaces (Klemenz and Scheel 1993). 

Figure 31.2 Observation by differential interference contrast (Nomarski) fluorescence optical microscopy of the transformation from a tubular structure to an oligovesicular structure of phospholipid (A) suspended in a phosphoric buffer (T = 298 K, pH = 7.0, = 485 nm,...

The modern version of interference microscopy is differential interference contrast (also called Nomarski contrast, or DIG). Here again, the illumination is split into two beams, one of which is displaced at the specimen plane [1,5,6, 21]. In DIG, the beam is displaced a very small distance, much smaller than the beam diameter. The beams remain independent because the beam-splitting device is a doubly refracting crystal, producing two beams in perpendicular polarization states (see Section 3.1.7). A region... 

---