Schematic diagram of the SDPM system is shown in Fig. 1. A super-luminescent diode (SLD) (Superlum, central wavelength 840 nm, FWHM spectrum bandwidth of 50 nm, 15 mW fiber output power) light passes through a polarization controller and is split using a fiber coupler. One of the outputs from the coupler is collimated using a spherical lens with 5-cm focal length, and focused onto the sample using a microscope objective, yielding a transverse resolution limit of approximately 0.6 μm. The sample is placed in a closed chamber such that the reflection from the upper surface of the chamber is used as the reference beam and the light reflected from the bottom surface, after passing through the cells and the media, is used as the sample beam. To increase the bottom surface reflection and thus improve the SNR, we used sputter deposition to coat the bottom glass surface by a thin layer of chrome for adhesion, and then by additional layer of gold over it creating an inert reflective surface. The combined reference and sample beams pass back through the fiber coupler to a compact spectrometer (Ocean Optics , 2048 pixel CCD, spectral range 718 to 900 nm, best efficiency 650 to 1100 nm) where the interference pattern is recorded. As shown in Fig. 1, to be able to locate the object of interest, a compact digital camera arm was added to the system. The camera arm consists of a 15-cm focal-length spherical tube lens and a compact CMOS camera (Thorlabs, monochrome CMOS camera, with of each). The tube lens and the objective lens are in 4f configuration. The camera displays the SLD beam and the bright field sample image simultaneously, and allows the correct positioning of the SLD beam over the chosen RBC (see Fig. 2).