The development of optical and quasi-optical (terahertz) refractometric technologies for characterizing basic fundamental parameters, namely, the refractive indices of isotropic and anisotropic materials, is based on two working experimental installations developed and created by us (see below and on our website: https://itne.lpnu.ua/equipment.html for a general view of one of them).
These installations correspond to the best world analogues.
The essence of the proposed scientific and technical development is to improve, based on the ideas of our patents (see below) by creating a more compact device with a simplified and automated measurement process and developing appropriate software for processing experimental results, which will increase accuracy and simplify the measurement process.
In developing the https://itne.lpnu.ua/equipment/mickelson.html technology, we used a number of our patented priorities, namely: 1) for the first time, a working relationship was derived for the direct calculation of the refractive index using the interferometric rotation method based on the measured angle of rotation of the sample under study in one of the arms of the interferometer and the corresponding shift in the interferometric pattern; 2) for the first time, it was shown that this method can be used to measure the refractive indices of both uniaxial and biaxial crystals; 3) in order to achieve higher accuracy of refractive index measurements, it was established that it is necessary to take into account the refractive index of air nsur. = 1.000294; 4) for the first time, the possibility of performing corresponding measurements using the interferometric-rotational method for samples with insignificant uncontrolled non-parallelism or deliberately specified wedge shape was demonstrated.
Key benefits of the developed devices:
1) simplification of the process of measuring and processing experimental data, which ensures increased accuracy of refractive index measurement;
2) automation, which provides rapid express analysis of the refractive indices of plane-parallel samples of optical materials with high accuracy;
3) the theoretically calculated error in determining the refractive indices on an optical experimental setup is 3.5x10-6 = 0.0000035. Based on the experiment, the following values were actually obtained: n0=2.2868±0.0002, ne=2.2032±0.0002 for LiNbO3 crystals and n0=1.5436±0.0005, ne=1.5527±0.0005 for crystalline quartz.
The use of interferometric-rotational measurement technology makes it possible to:
1) perform non-destructive testing, which ensures full compliance of the measurement parameters of samples in their further practical application;
2) measure all refractive indices of anisotropic media, including for uniaxial and biaxial crystals of any symmetry class on a single section, thereby saving expensive crystalline material;
3) the ability to determine the dispersion of optical refraction coefficients by using several sources of coherent radiation.
The proposed setup can be successfully used both for scientific research and for non-destructive express measurements of the refractive indices of parallel plates made of isotropic and anisotropic materials in industrial laboratories or in the production facilities of enterprises and companies engaged in the cultivation of amorphous or crystalline materials. parallel plates made of isotropic and anisotropic materials in industrial laboratories or in the production facilities of enterprises and companies engaged in the cultivation of amorphous or crystalline materials and the creation of optoelectronic devices based on them.