## 1 Introduction  
Interferometric techniques take advantage of light interference, which is a phenomenon that occurs when two or more coherent waves, i.e., with the same wavelength, amplitude, and linearly polarized vibration planes, overlap in space; interference (constructive-destructive) can be observed in the form of bright and dark fringes when projecting the interfering beams onto a screen. If two waves in a vacuum interfere, the phase difference (\(\Delta\phi\)) with which they arrive at the point of interference is due to the difference in the length of the optical paths (OPD) traveled by each wave [1]. Depending on the interference pattern morphology and the experimental conditions, the most suitable method to calculate the complete phase difference map is selected, since each method has its own advantages and disadvantages. For example, when analyzing a dynamic sample whose interference generates open fringes, the Fourier method is commonly chosen because it requires only one interferogram that is captured in a fraction of a second [2]; on the other hand, if the sample is static or quasi-static, and the interference fringes are closed, a phase-shifting method is usually applied, which requires capturing several interferograms [2]. The optical setup designed to generate the light interference is called an optical interferometer. Through the fringe pattern generated by light interference, it is possible to measure physical quantities of objects such as Young's modulus, topography, mechanical stress, temperature, refractive index, etc. Over the years, interferometric techniques have been combined with various optical techniques, such as in tomographic phase microscopy in flow cytometry [3], optical tweezers to carry out biological characterizations [4], holographic optical tweezers [5; 6; 7], or optical trap spectroscopy [8]. Although the most common applications of optical tweezers are in biology [9; 10] and in micromanipulation of other types of particles [11], applications are not limited to these functions. On the other hand, in 1970, [PERSON] reported particle trapping using the radiation pressure force of a continuous laser [12]. Radiation pressure (\(P_{rad}\)), at normal incidence, is determined with the expression \(P_{rad}=I(R+1)/c\), where \(I\) is the irradiance, \(R\) represents the surface reflection coefficient, and \(c\) is the speed of light [13]. When the beam emitted by a laser is focused via a lens, the pressure at the beam waist will be higher than in the rest of its optical path and will be directed toward the beam center. This makes it possible to keep a micrometer- or sub-micrometer-scale particle trapped in the beam waist, which gives it the name optical trap. The use of different laser power levels for optical traps has been reported in the literature, ranging from a few mW to a Watt or more in the specimen plane, depending on details of the laser and setup, objective transmittance, and the desired stiffness [14]. Generating an efficient optical trap requires that the beam focused via the lens comes from a large Numerical Aperture (NA); therefore, it is necessary to use an immersion microscope objective (100X and NA \(\approx 1.3\)). However, many radiation pressure studies neglect the optical contributions of immersion media used for their implementation [15; 16; 17], often due to their transparent nature, or simply because such media are a constant in every optical trap. Common immersion media, such as water or oil, have effects of the same type but on a different scale; thus, their contributions are a factor to consider in works that use immersion where trap geometry is of interest, or where interferometric quantifications are performed through phase recovery [18]. Phase is a particular characteristic of waveform cycle, usually expressed in terms of angular units. Phase changes are relevant in the context of light interference effects, and this will be further discussed in Section 2.