Testing with a single holographic lens or grating in a collimated beam is normally not possible because of the inherent tilt caused in the wavefront. The tilt between the two beams in shearing creates a large number of linear fringes which overshadow the information about the wavefront. However, here, we show that we can use this tilt to make quantitative measurements which was otherwise not possible. In the novel method, we obtain shear in a relatively simple way, and at the same time we extract phase information using spatial Fourier transform technique. This technique is suitable for making quantitative measurement of wavefront and disturbances in turbulent conditions. Here, we demonstrated the real-time phase measurement capacity of the interferometer, a result of one such application is shown.

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The results of a study of a plasma jet of atmospheric-pressure helium driven by a capacitive discharge using sine and pulsed modes of excitation are presented. The homogeneous discharge of a multi-channel plasma jet at gas temperature of 34 °C and helium flow rate of 0.5 L/min was achieved with short pulse excitation. A digital holography method is proposed to estimate a basic plasma parameter, i.e., its electron concentration. An automated digital holographic interferometry set-up for the observation and study of a nonthermal plasma jet in a pulse mode is developed and described. The synchronization features of recording devices with the generation of plasma pulses are considered. The electron concentration of the plasma jet is also estimated. The disadvantages of the proposed technique and its further application are discussed.

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