Nanooptics and photonics

The holographic method of determination of refractive index of liquid objects 
Davidenko N.A., Davidenko I.I., Pavlov V.A., Chuprina N.G., Kuranda N.N., Mokrinskaya E.V.
Kiev Taras Shevchenko National University
Volodymyrs’ka Str., 64/13, Kyiv-01601, Ukraine. 
E-mail: ndav@univ.kiev.ua

The photothermoplastic medium based on the films of photosensitive polymeric composites with semiconductor properties is developed for application in optical information recording and storage, in holographic interferometry as well as for medical purposes. The present work is aimed at creation of new cooligomer providing higher diffraction efficiency when it is used as the holographic recording media (HRM) base for photothermoplastic (PTP) holographic recording as well as at employing these HRM for determination of the refractive index of the liquid and gaseous objects. Cuvette without diffuser and reversible holographic medium without “wet” development of the holograms were used. With the aim to increase the precision of measurements of the refractive index, the method of phase steps (Phase Shifting Interferometry) of analysis of the interferograms was applied. This medium was used in the modified holographic device for determination of the refractive index of homogeneous and inhomogeneous liquid and gaseous objects. To reach the aim of the present work, above described HRM were used for determination of the refractive index (n) of liquid and gaseous objects. The method includes transmission of the coherent irradiation through trapezoidal cuvette alternately fillable with standard and investigated media, registration of the hologram, its reconstruction and determination of the n value by measurement of the spatial frequency of interference strips using Phase Shifting Interferometry.
The technique and holographic equipment were modified by employing the specially developed and produced transparent cuvette of special shape. Method of “phase steps” was used for the interferograms processing. Experimentally demonstrated precision of the measurements is not less than 10-5.