Phase and Polarization Contrast Methods by Use of Digital Holographic Microscopy: Applications to Different Types of Biological Samples

Polarization-Sensitive Digital Holographic Imaging for Characterization of Microscopic Samples: Recent Advances and Perspectives

“…Computing the Fourier transform of the acquired hologram, these terms appear spatially separated in the Fourier space, due to the off-axis configuration, as well shown in Figure 2b where the presence of some parasitic interferences are also highlighted [16,29]. In order to recover the information of the real images, the corresponding spectra could be selected by two different spatial filters [15,18].…”

“…It consists of a modified Mach-Zehnder interferometer with two reference waves-R 1 and R 2 -that interfere with the object beam O [11,[15][16][17]. Two operating conditions are possible [18]. First, the object plane beam is linearly polarized by a polarizer (P1 oriented at 45 • ) and a quarter wave plate (QWP1 oriented at 0 • respect the incoming light).…”

“…As with classical holography, the reconstruction is obtained by multiply the digital hologram for a digitally computed reference wave and then the inverse Fourier transform of the spatial frequency components filtered is performed. By using the standard reconstruction algorithm on each filtered region, the two orthogonal components of the object beam (O x and O y ), can be retrieved [15,16,18,30]. So, the amplitude map and the phase map for each polarization component can be reconstructed.…”

“…During the last decade, DHI has experienced several technological developments, including the integration of DHI with complementary characterization techniques (e.g., Raman spectroscopy or scanning electron microscope [11][12][13]). A further important extension of DHI is the possibility to quantitative measure the state of polarization (SoP) modified by a sample [14][15][16][17] and so evaluate its birefringent and/or dichroic proprieties, which are frequently related to the micro-or even ultra-structure of the sample itself [18]. Therefore, the characterization of these proprieties and the detection of their eventual variations, that can be due to either stress and strain in a given material or disordered microstructure in biological specimens, could lead to a better understanding of the process involved in a broad variety of applications.…”

Técnicas de microscopia holográfica digital aplicadas à análise de sistemas biológicos

“…Além disso, a literatura é omissa sobre a aplicação da MHP a medidas de dicroísmo. Pesquisadores relatam a possibilidade teórica dessa aplicação, mas ainda não se encontram relatos dessa utilização [24].…”