Single-scan multiplane phase retrieval with a radiation of terahertz quantum cascade laser

Terahertz phase retrieval from a set of axially separated diffractive intensity distributions is a promising single-beam computational imaging technique that ensures the obtention of high spatial resolutions and phase wavefronts, but remains restricted by time-consuming data acquisition processes. In this work, we have adopted an approach, relying on the radiation of a quantum cascade laser and the implementation of an express single-scan measurement of intensity distributions through the continuous on-the-go displacement of a high-sensitivity antenna-coupled microbolometer sensor array. In addition to the simplicity of this practical implementation and the minimization of measurement times, such an approach overcomes the problem of preliminary optimal selections of transverse intensity distributions used in the iterative phase retrieval algorithm and guarantees the required data diversity for high-quality wavefront reconstruction

Necessity and Use of a Multilayer Test Object Based on an Anonymous 19th Century Copy of a Painting by Ivan Konstantinovich Aivazovsky (1817–1900)

The emergence of new research methods in the field of heritage science always raises a large number of questions related to their applicability, reproducibility of results on similar objects, complementarity with other methods, and development of new research methods. To solve such problems, it is necessary to have a test object with the required structure. A multilayer test object based on a fragment of a copy of a 19th century painting by I.K. Aivazovsky was created and described. Analytical studies of the colourful layers were carried out on a Fourier-transform infrared (FT-IR) spectrometer with an attenuated total reflectance (ATR) attachment in single-reflection mode with a diamond crystal. As part of the use of one research method, differences between painting layers of the 19th and 20th centuries were revealed. Results are presented in the IR graphs. The aim of the work was to identify the characteristics of the pictorial layers inherent in the copy of the painting by I.K. Aivazovsky. This will improve the methodology of technological expertise of the I.K. Aivazovsky’s artworks

Necessity and Use of a Multilayer Test Object Based on an Anonymous 19th Century Copy of a Painting by Ivan Konstantinovich Aivazovsky (1817–1900)

The emergence of new research methods in the field of heritage science always raises a large number of questions related to their applicability, reproducibility of results on similar objects, complementarity with other methods, and development of new research methods. To solve such problems, it is necessary to have a test object with the required structure. A multilayer test object based on a fragment of a copy of a 19th century painting by I.K. Aivazovsky was created and described. Analytical studies of the colourful layers were carried out on a Fourier-transform infrared (FT-IR) spectrometer with an attenuated total reflectance (ATR) attachment in single-reflection mode with a diamond crystal. As part of the use of one research method, differences between painting layers of the 19th and 20th centuries were revealed. Results are presented in the IR graphs. The aim of the work was to identify the characteristics of the pictorial layers inherent in the copy of the painting by I.K. Aivazovsky. This will improve the methodology of technological expertise of the I.K. Aivazovsky’s artworks

Optical Properties of Crystalline Lactose Fluidized with Dilutions of Various Substances in the Terahertz Frequency Range

Lactose is a commonly used component of pharmaceutical medications in tablet form. It was previously shown that lactose changes conformationally after saturation in fluidized beds with active pharmaceutical ingredients obtained by repeated dilution of antibodies to interferon-gamma in combination with an external intensive vibration treatment. Moreover, it was revealed that these solutions are self-organized dispersed systems in which nano-objects are formed. Their biological activity and mechanism of action were previously established as well. The current work was dedicated to investigating the optical properties of fluidized lactose powders in the terahertz frequency range. Spectral analyses of powders of crystalline lactose saturated in fluidized beds with a diluted solution of either glycine buffer, antibodies to interferon-gamma, or water were carried out, intact lactose served as a control. All powders were tableted before testing. In the course of the study, the macroscopic parameters of the tablets were established, at which they had a stable shape and their THz optical properties had no parasitic diffraction losses. These tablets were analyzed using terahertz time-domain spectroscopy in the frequency range of 0.2–2.6 THz. The differentiation between the spectra was conducted using a principal component analysis. The differences between intact lactose and the lactose saturated with any of studied solutions were demonstrated. Additionally, lactose saturated with solutions of multiple dilutions of a substance (antibodies or glycine buffer) differed not only from intact lactose, but also from lactose saturated with a diluted solution of water. Moreover, discrimination of lactose formulations saturated with different substances (antibodies or glycine buffer) was also possible. Additionally, intact lactose differed from lactose saturated with diluted water. The methods reported could be useful for the quality control of the medications based on the technology of repeated dilution of an original substance

Reconstructed THz phase image of the two-component numerical model of breast cancer tissue

International audienc

Agar and Silica Gel Based Biotissue-mimicking Phantoms in THz Frequency Range

International audienc

The terahertz pulse time-domain holography method for phase imaging of breast tissue sample

International audienc

A comparison of terahertz optical constants and diffusion coefficients of tissue immersion optical clearing agents

We performed the transmission-mode terahertz (THz) pulsed spectroscopy of several THz-wave penetration- enhancing agents (PEAs): glycerol, propylene glycol, ethylene glycol, and polyethylene glycol, featuring the molecular weight of 200, 300 and 400. We vacuumized the THz beam path in order to reduce an impact of water vapor on measured data. We reconstructed optical properties and dielectric constants of the abovementioned PEAs in the spectral range of 0.1 to 2.5 THz. We analyzed measured THz optical properties along with the literature data for coefficients of PEAs' diffusion into tissues in order to objectively uncover strength and weaknesses of their use in the immersion optical clearing of tissues at THz frequencies

Study of blood plasma optical properties in mice grafted with Ehrlich carcinoma in the frequencyrange 0.1–1.0 THz

International audienceIn the course of in vitro studies of blood of laboratory animals with progressing Ehrlich carcinoma, we have revealed the change of the blood plasma optical properties in the THz range, which can be used for developing the express diagnostics of the presence of oncological diseases. An applied software package is elaborated that allows the phantoms of biological samples having a complex structure to be numerically simulated and the parameters of the electromagnetic wave reflected from these samples in the THz frequency range to be calculated

JPCS

Abstract The goal of this study was to detect and inspect the paint layers below the surface independently of any surface features. Using the for THz-TDS imaging system, we obtained contrast images of layers of paint applied to the back side of the canvas. The most difficult task that the researchers have set themselves has not yet been fully resolved. When we try to read the signatures through several layers of paint, background and canvas, we cannot get a clear image of the letters, but we can accurately determine the location of all the signatures