Patent ID: 8520215

Claim:
A method of investigation of volume change dynamics of physiologically active samples exposed to a source of visible radiation comprising: splitting a source beam of monochromatic highly coherent radiation produced by a laser source in two mutually perpendicular beams on a first beam splitter, of which a measuring beam falls via an adjustable mirror on a reflective target with highly reflective surface, which is in mechanical contact with a surface of a measured sample, and a reference beam falls on a fixed reference reflective mirror, after reflection and backward pass through the first beam splitter the measuring beam and the reference beam interfere, determining a transversal change of the measured sample surface position as a consequence of a volume change of the measured sample from a phase difference of harmonic waves in an interfering radiation beam, splitting the interfering radiation beam into two detection beams on a second beam splitter, where the first detection beam passes through a first converging lens and falls simultaneously on a first photodetector and on a second photodetector, while the first and second photodetectors are mutually phase-shifted by 90″ in a resultant interferogram, and the second detection beam, perpendicular to the first detection beam falls on a third photodetector, which scans a whole interference pattern, while the first and second detection beams before respectfully falling on the first and second photodetectors pass through absorbers of diffuse radiation, formed by cylindrical tubes whose length is an order multiple of a length of the first and second photodetectors, wherein signals from the first and second photodetectors lead to a processing unit, connected to a computer via an interface and signals from the first and second photodetectors lead to a basic module in a measuring unit, where a third reference photodetector after being processed in an amplifier gives a mean value of radiation intensity as a reference level in a reference signal, and signals from the first photodetector and the second photodetector, after processing in amplifiers and after suppressing of noise signals by low-pass type active filters, are transferred to symmetric alternating signals with suppressed direct component by the reference signal, separating the alternating component of the second photodetector signal by a signal shaper, taking samples of alternating signals from the first photodetector and from the second photodetector by a controlling and sequential circuit, transmitting controlling signals for sampling amplifiers to eliminate disturbing effects, and measuring with high amplitudes and voltage corresponding to frequencies of noise signals on the output from the controlling and sequential circuit, while the basic module is connected to the computer through three A/D converters and an interface.