The phase contrast microscope is a vital instrument in biological and medical research; it facilitates the observation of living cells by using spatial light modulation to enhance the intrinsic contrast of transparent and colorless components in a cell. It can reveal cell structure without the need of contrast agents. However, the information obtained is only qualitative.
Jones Phase Microscopy (JPM) and White Light Quantitative Phase Microscopy (PC++) of transparent and anisotropic samples are novel interferometric techniques that are quantitative and polarization sensitive. They are capable of quantifying the optical phase delays associated with live cell samples while providing information about the morphology and dynamics.
Quantifying these optical path length shifts allows for nanometer scale measurements with broad applications in nanotechnology and life sciences, e.g. from inspecting semiconductor wafers to studying processes in live cells.
Description/Details
Jones Phase Microscopy (JPM) technique is capable of extracting the spatially-resolved Jones matrix associated with transparent and anisotropic samples. It can provide the quantitative phase image of the cells as well as the intrinsic structure details and dynamics. JPM setup consists of a modified Hilbert Phase microscope; the quantitative phase image is correlated to the sample using a 2D spatial Hilbert transform. The full Jones matrix in each point within the field associated with the transparent sample is extracted and the embedded quantitative information of phase delay is used to reconstruct its image.
The White Light Quantitative Phase Microscope (PC++) interfaces with a commercial phase contrast microscope and transforms it into a quantitative instrument by performing two additional measurements (hence the name PC++). In a conventional phase microscope the additional phase delay is introduced by the phase objective, the PC image is delivered at the image plane and recorded by a CCD. However, in PC++, the optical field at the image plane is further modulated before detection which is equivalent to spatial filtering with three different phase masks and reconstruction of image by addition of fields containing information about the unscattered light (forming the uniform background) and the fine structural details (the contrast).
Applications
- Optical microscopy and imaging of: live cells and thin tissue slices; microorganisms; lithographic patterns and nanoparticles
- Study of cell dynamics and morphology
Benefits
- These techniques provide improved contrast in unstained biological specimens and can be utilized to examine dynamic events in living cells.
- Quantitative Phase delay information
- Polarization sensitive imaging: while Jones Phase Microscope is a modified Hilbert Phase microscope, the PC++ is an add-on to a commercial phase contrast microscope.