ПРИМЕНЕНИЕ УСТРОЙСТВ ДЛЯ ПРОСТРАНСТВЕННО-РАЗРЕШЕННОЙ СПЕКТРОСКОПИИ НА ПРИМЕРЕ ДВУХСЛОЙНЫХ ФАНТОМОВ, СОДЕРЖАЩИХ МЕТАЛЛИЧЕСКИЕ НАНОЧАСТИЦЫ

The abilities of the optical probe for fluorescence-guided stereotactic biopsy were investigated by means of a multifiber probe under 532 or 632.8 nm excitation. The set of multilayered phantoms representing a border between normal brain-tissue and a tumor with photosensitizer and gold nanoparticles (spheres or stars) in different concentrations were made to investigate the macroscopic parameters observed during the neurosurgical biopsy sample collection by means of the optical probe. These investigantions will allow to define the border of a brain tumor and control the type of tissue being collected by a stereotactic cannula during surgery. The impact of gold nanospheres and gold nanostars added in different concentrations to the bottom-layer of phantom was analyzed by fluorescence quenching or enhancement due to energy transfer between nanoparticles and fluorescent molecules. The results allow determining the tumor border and to make the biopsy uptake more efficient by observing the character of signal change while penetrating a tumor and while going out of it.Исследованы возможности применения зонда для стереотаксической биопсии при флуоресцентной навигации при возбуждении 532 или 632,8 нм. Для исследования макроскопических параметров, наблюдаемых во время забора образцов при стереотаксической биопсии с помощью оптического зонда, был сделан набор полужидких, полутвердых многослойных фантомов, моделирующих границу между нормальной мозговой тканью и опухолью с фотосенсибилизатором и наночастицами золота (сферы и звезды) в различных концентрациях. Было проанализировано влияние золотых наносфер и нанозвезд, добавленных в разных концентрациях к нижнему слою фантома, на усиление флуоресценции за счет переноса энергии между наночастицами и флуоресцентными молекулами. Результаты позволяют определить границу опухоли и повысить эффективность биопсии, наблюдая характер изменения флуоресцентного сигнала при прохождении зонда через опухоль

APPLICATION OF DEVICES FOR SPACE-RESOLVED SPECTROSCOPY ON THE EXAMPLE OF TWO-LAYER PHANTOMS CONTAINING METALLIC NANOPARTICLES

The abilities of the optical probe for fluorescence-guided stereotactic biopsy were investigated by means of a multifiber probe under 532 or 632.8 nm excitation. The set of multilayered phantoms representing a border between normal brain-tissue and a tumor with photosensitizer and gold nanoparticles (spheres or stars) in different concentrations were made to investigate the macroscopic parameters observed during the neurosurgical biopsy sample collection by means of the optical probe. These investigantions will allow to define the border of a brain tumor and control the type of tissue being collected by a stereotactic cannula during surgery. The impact of gold nanospheres and gold nanostars added in different concentrations to the bottom-layer of phantom was analyzed by fluorescence quenching or enhancement due to energy transfer between nanoparticles and fluorescent molecules. The results allow determining the tumor border and to make the biopsy uptake more efficient by observing the character of signal change while penetrating a tumor and while going out of it

Spectral control of high order harmonics through non-linear propagation effects

International audienceigh harmonic generation (HHG) in crystals has revealed a wealth of perspectives such as all-optical mapping of the electronic band structure, ultrafast quantum information, and the creation of all-solid-state attosecond sources. Significant efforts have been made to understandthe microscopic aspects of HHG in crystals, whereas the macroscopic effects, such as non-linear propagation of the driving pulse and itsimpact on the HHG process, are often overlooked. In this work, we study macroscopic effects by comparing two materials with distinct optical properties, silicon (Si) and zinc oxide (ZnO). By scanning the focal position of 85 fs duration and 2.123 lm wavelength pulses inside thecrystals, (Z-scan) we reveal spectral shifts in the generated harmonics. We interpret the overall blueshift of the emitted harmonic spectrumas an imprint of the spectral modulation of the driving field on the high harmonics. This process is supported with numerical simulations.This study demonstrates that through manipulation of the fundamental driving field through non-linear propagation effects, precise controlof the emitted HHG spectrum in solids can be realized. This method could offer a robust way to tailor HHG spectra for a range ofapplications