Rajdeep Deb, featured ILCC liquid crystal artist, May 2009
Rajdeep Deb being ICAM-I2CAM Junior Exchange Awardee joined the Liquid crystal Material Research Center, University of Colorado at Boulder. Here he is studying the most spectacular defects and structures in B7 phase (such as spirals, ribbons, checkerboard …) using fluorescence confocal microscope imaging technique in Prof Ivan I Smalyukh’s Lab.
The fluorescence confocal microscope image is a co-localized combination of two fluorescence textures obtained using two different polarization states of the linearly polarized excitation laser beam shown in two-colour scheme viz. blue and green. The fluorescence depicted in blue colour refers to vertical FCPM polarization while the green one is for horizontal polarization.
Prior joining the Liquid Crystal Center and this ICAM-I2CAM exchange program he worked in Department of Chemistry, Assam University, India as a graduate research assistant in Prof. Nandiraju V S Rao’s group. His doctoral dissertation work is directed toward tailoring liquid crystal bent-core compounds by incorporating emissive properties to such systems while retaining their liquid crystalline properties.
Mr. Deb’s research experience is characterized by his work in one of the formidable challenges associated with present day chemical synthesis i.e. the construction of molecular self assemblies with tailor made properties. His current research interests encompass different branches of soft condensed matter and optical physics, including novel laser trapping and fluorescence confocal imaging techniques which he is presently perusing, apart from synthesis of functionalized molecular electronic materials.
The picture shows the fluorescence confocal polarizing microscope (FCPM) structures in B7 phase formed by the emissive banana liquid crystal. The corresponding 'normal' polarized microscopy picture is shown below, right. The texture grows in with a widely variegated morphology of domains with developable ribbons having equally spaced lines and focal conic domains.
The picture was taken on an Olympus Fluoview FV5 confocal microscope, modified by a linear polarization rotator that sets polarization of the excitation beam and the polarisation of the detected fluorescent light and the image size is 512X512μm; the corresponding transmission polarizing microscopy image was taken with Nikon D300 digital camera.
Jury comment: the application of a modern and very useful imaging technique to one of the most beautiful liquid crystal phases known results in a picture that is very graphical in nature, the true image condensed to a few distinct geometrical features and only two colors. In all its beauty, the fluorescence image also complements the standard texture information-wise, as it distinguishes two perpendicular polarizations, neither of which gives rise to any color in polarizing microscopy.