Combined Photothermal Lens and Photothermal Mirror Characterization of Polymers

Aréstegui, Odon S.; Poma, P.Y.; Herculano, Leandro S.; Lukasievicz, Gustavo V. B.; Guimarães, F.B.; Malacarne, L. C.; Baesso, Mauro Luciano; Bialkowski, Stephen E.; Astrath, N. G. C.

doi:10.1366/13-07404

Cited by 15 publications

(6 citation statements)

References 42 publications

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“…1.555 À4:5 Â 10 À6 --CAS7 17 1.66 6:9 Â 10 À6 --CAS35 17 1.61 4:5 Â 10 À6 --PC 20 1.584 À1:01 Â 10 À4 --PMMA 20 1. In the TM technique, the probe beam interacts only with one interface, while in the TL technique the beam passes through two interfaces.…”

Section: Influence On Photothermal Signalmentioning

confidence: 99%

“…For the TL technique, the properties used were those of two semi-transparent samples, polycarbonate (PC) and CAS35. 8,17,20 Figure 2a shows results for cw laser excitation, whereas a pulsed laser excitation is considered in Figure 2b. The phase shift solutions used are those described in the literature for cw excitation and pulsed excitation.…”

Section: Influence On Photothermal Signalmentioning

confidence: 99%

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Analysis of the Thermo-Reflectivity Coefficient Influence Using Photothermal Pump–Probe Techniques

et al. 2016

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Recent improvements in the modeling of photo-induced thermo-optical-mechanical effects have broadened the application of photothermal techniques to a large class of solids and fluids. During laser excitation, changes in optical reflectivity due to temperature variation may affect the photothermal signal. In this study, the influence of the reflectivity change due to heating is analyzed for two pump-probe photothermal techniques, thermal lens and thermal mirror. A linear equation for the temperature dependence of the reflectivity is derived, and the solution is tested using optical properties of semi-transparent and opaque materials. For semi-transparent materials, the influence of the reflectivity change in photothermal signals is less than 0.01%, while for opaque materials it is lower than 3%.

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Section: Influence On Photothermal Signalmentioning

confidence: 99%

Section: Influence On Photothermal Signalmentioning

confidence: 99%

Analysis of the Thermo-Reflectivity Coefficient Influence Using Photothermal Pump–Probe Techniques

et al. 2016

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“…В процитированных работах в качестве экспериментальных данных использовались результаты фотометрических измерений коэффициентов пропускания и отражения. В случае образцов с большой оптической плотностью более удобными становятся фототермические методы исследования, такие как термическое зеркало [19] и оптоакустическая спектроскопия [20][21][22]. В работе [23] предложена методика моделирования оптоакустических сигналов, инициируемых лазерным импульсом в поглощающей среде с упругим рассеянием излучения.…”

Section: Introductionunclassified

Оптоакустическое Исследование И Моделирование Оптических Свойств Композитов Циклотриметилентринитрамин-Ультрадисперсные Частицы Никеля

Aduev¹,

Нурмухаметов²,

Zvekov³

et al. 2020

Журнал Технической Физики

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Экспериментально получены оптоакустические сигналы, инициируемые импульсным лазерным излучением (длительность импульса на полувысоте 14 ns) с длиной волны 532 nm в прессованных композитах циклотриметилентринитрамин (RDX) -ультрадисперсные частицы никеля, и определены их наблюдаемые показатели поглощения излучения при значениях среднего радиуса частиц 40, 60, 80 и 140 nm. Показано, что зависимость экспериментального показателя поглощения от радиуса частиц при постоянной массовой доле немонотонная. Результаты интерпретировались в рамках теории переноса монохроматического излучения. Показано, что согласие экспериментальных и рассчитанных значений показателя поглощения прессованных таблеток RDX-ультрадисперсные частицы никеля различного радиуса достигается при учете остаточной пористости образца. Оценены средний радиус пор и их концентрация. Ключевые слова: оптоакустическая спектроскопия, ультрадисперсные частицы металлов, RDX, уравнение переноса излучения.

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“…This comprises the determination of low optical absorption coefficients, 20,21 Soret effect, 22 investigation of photobleaching processes, characterization of mass and thermal diffusion properties of fuels and biofuels, [23][24][25][26] dyes, [27][28][29] micellar solutions, 30 and photosensitizers. [31][32][33][34] The method can also be used to study thermal and optical properties of polymers and glasses, [35][36][37][38][39][40] in addition to the pharmacological and biological applications and determination of heavy metals. [41][42][43][44][45] There have been several reviews on TL applications in the literature.…”

Section: Introductionmentioning

confidence: 99%

From Protohypericin to Hypericin: Photoconversion Analysis Using a Time-Resolved Thermal Lens Technique

et al. 2019

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Hypericin (Hyp) is a natural compound with interesting photophysical and pharmacological properties, which has been used in photodynamic therapy and photodynamic inactivation of microorganisms. Its synthesis is based on a series of chemical processes that ends with a light–drug interaction by the photoconversion of protohypericin (pHyp) to Hyp. Although this photosensitizer is used in a variety of medical applications, the photophysical and photochemical mechanisms involved in the final step related to the photo production of Hyp are not completely understood at the molecular level. Protohypericin concentration, solvents, light irradiation under different wavelengths, and a sort of variables could play an important role in predicting the yielding of this photoconversion process. Here, we used the high-sensitive and remote measurement characteristics of the time-resolved thermal lens technique to investigate the relation between the light-induced photoconversion rate of pHyp to Hyp and the initial concentration pHyp. The results show a linear dependence of the photoreaction rate with the concentration of pHyp, indicating that the overall reaction process includes steps comprising the formation of distinct intermediate species. We demonstrate the applicability of the thermal lens technique for the photochemical characterization of photosensitive drugs at low concentration levels.

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Combined Photothermal Lens and Photothermal Mirror Characterization of Polymers

Cited by 15 publications

References 42 publications

Analysis of the Thermo-Reflectivity Coefficient Influence Using Photothermal Pump–Probe Techniques

Analysis of the Thermo-Reflectivity Coefficient Influence Using Photothermal Pump–Probe Techniques

Оптоакустическое Исследование И Моделирование Оптических Свойств Композитов Циклотриметилентринитрамин-Ультрадисперсные Частицы Никеля

From Protohypericin to Hypericin: Photoconversion Analysis Using a Time-Resolved Thermal Lens Technique

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