Dynamic temperature field measurements using a polarization phase-shifting technique

Abstract

In this study, an optical system capable of simultaneously grabbing three phase-shifted interferometric images was developed for dynamic temperature field measurements of a thin flame. The polarization phaseshifting technique and a Michelson interferometer that is coupled to a 4-f system with a Ronchi grating placed at the frequency plane are used. This configuration permits the phase-shifted interferograms to be grabbed simultaneously by one CCD. The temperature field measurement is based on measuring the refraction index difference by solving the inverse Abel transform, which requires information obtained by the fringe order localization. The phase map is retrieved by a three-step algorithm. Experimental results of a dynamic thin flame are presented.

Common path interferometer based on the modified Michelson configuration using a reflective grating

“…2(a). The three phase-shifted interferograms can be separated and then matched to each other by feature points, which can be generated by using an iris diaphragm [22,25]. The optical path difference (OPD) distribution of the specimen can be retrieved as shown in Fig.…”

“…To achieve the interferograms with comparable intensities, as many others did [16,21,22], only orders 0 and 71 of the object beams can be considered during the process of interference. The intensity distributions of the three phase-shifted interferograms formed by the reference and object beams of orders 0 and 7 1 in the output plane, respectively, can, then, be expressed as…”

“…To solve the amplitude interferogram modulation caused by the grating [11,21,22], the normalized algorithm [16] is utilized to retrieve the phase distribution of the measured specimen as follows:…”

4D measurements of biological and synthetic structures using a dynamic interferometer

“…The function of coupled Michelson interferometers, is to replicate the incident interferogram, similar to the effect generated by a diffraction grating, but without disadvantages of the modulation of the fringes. The For this study, a microscope system has been added at the entrance of the PSTI, with a microscope objective (MO) with magnification of 60X, for the purpose of being able to analyze biological samples, such as red blood cells and the legs of a pseudoscorpion (24)(25)(26) which are analyzed using the interferometer in non-shearing mode (27)(28)(29)(30). The microscope objective has a numerical aperture of 0.85, the working distance is 0.3 mm (wavelength range 400-700 nm), the effective focal length is 2.9 and the clear aperture is 4.5 mm.…”

Digital holography for temperature investigations in space and transparent media

“…Comparing the proposed method to earlier ones [13][14][15][16], the calculating procedure is made simpler, increasing computational efficiency. The approach, which does not require the use of challenging mathematical inversions [1,17,18], determines the relationship between phase changes and temperature variations based on the temperature coefficient of the refractive index.…”