We present a multispectral polarimetric imaging system well suited for complete Mueller matrix microscopy. The source is a spectrally filtered halogen light bulb, and the image is formed on a fast CCD camera The light polarization is modulated before the sample and analyzed after the sample by using nematic liquid crystal modulators.. The whole Mueller matrix image of the sample is typically measured over 5 seconds for a good signal-to-noise ratio. The instrument design, together with an original and easy-to-operate calibration procedure provides a high polarimetric accuracy over wide ranges of wavelengths and magnifications. Mueller polarimetry provides separate images of scalar and vector retardation and dichroism of the sample, together with its depolarizing power, while all these effects do contribute simultaneously to the contrasts observed in standard polarized microsopy. Polarimetric images of several samples, namely an unstained rabbit cornea, a picrosirius red stained hepatic biopsy, and a rat artery specifically stained for collagen III are shown and discussed
We present a first evaluation of the interest of the degree of polarization (DOP) imaging technique for early detection of cervical dysplasia. A set of ten ex vivo samples of cervix have been examined, just after surgical extraction, with an DOP imaging system comprising two linear polarizers, a liquid crystal based polarization rotator, and fast CCD camera. Routine histological examination revealed that for all samples but one, dysplasia was present only in the inner part of the cervix, which cannot be imaged with our current setup. On the other hand, the only sample exhibiting dysplasia in its outer region did show nonzero DOP with, however, a somewhat loose correlation between the DOP and the histological mapping of the dysplasia.
We present a new polarimetric imaging system based on liquid crystal modulators, a spectrally filtered white light source and a CCD camera. The whole Mueller matrix image of the sample is measured in around 5 seconds in transmission mode. The instrument design, together with an original and easy-to-operate calibration procedure
provides a high accuracy (better than 1.5% for the normalized Mueller matrix) over a wide spectral range. The data can be processed with different algorithms. Results on hepatic biopsies with different grades of fibrosis are presented.
A very simple OCT system has been developed, based on a Linnik interferometric microscope with its reference mirror mounted on a piezoelectric translator. The geometrical extension of the optics allows efficient illumination of this device with a low power (3 W) light bulb, yielding full field interferometric images at 50 Hz acquisition rate with a fast CCD camera. Due to the very broad spectral width of the light source and camera response, a longitudinal resolution of 1.5 micrometers is achieved. Tomographic images of cell smears are shown.