Study of the effect introduced by an integrating sphere on the temporal profile characterization of short laser pulses propagating through a turbid medium

Morales-Cruzado, Beatriz; Pérez‐Gutiérrez, Francisco G.; Lange, D.; Romero‐Méndez, Ricardo

doi:10.1364/ao.54.002383

Cited by 3 publications

(5 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Our analysis assumed energy deposition in melanosomes in water, but energy deposition in epidermal melanosomes could be larger because the fluence rate in the tissue increases from that of an incident laser pulse owing to backscattering by the surrounding tissue 53 . Additionally, a temporal laser pulse profile stretches owing to multiple scattering by the tissue 54 . This effect may shift the energy deposition shown in Figure 6 to a value at a longer pulse width.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Nonlinear absorption‐based analysis of energy deposition in melanosomes for 532‐nm short‐pulsed laser skin treatment

et al. 2023

View full text Add to dashboard Cite

Background and Objectives: The clinical use of 532-nm short-pulsed lasers has provided effective treatment of epidermal pigmented lesions. However, the detection of significant differences in treatment effects between picosecond and nanosecond lasers has still varied among clinical studies. For robust evaluation of the differences based on the treatment mechanism, this study presents a nonlinear absorption-based analysis of energy deposition in melanosomes for 532-nm shortpulsed laser treatment. Study Design/Materials and Methods: Nonlinear absorption by melanin is modeled based on sequential two-photon absorption. Absorption cross-sections and nonradiative lifetimes of melanin, which are necessary for the nonlinear absorption-based analysis, are determined from transmittance measurement. Using the model and parameters, energy deposition in melanosomes was calculated with varying fluence and pulse width settings, including actual clinical parameters.Results: The energy deposition in melanosomes increased with shorter laser pulses, and subnanosecond laser pulses were found to be most efficient. The comparison of energy deposition calculated using clinical parameters demonstrated the differences in treatment effects between picosecond and nanosecond lasers reported in clinical studies. Conclusion:The nonlinear absorption-based analysis provides quantitative evidence for the safety and efficacy evaluation of short-pulsed laser treatments, which may lead to the establishment of numerical indices for determining treatment conditions. Future studies considering the effects of the surrounding tissue on energy deposition in melanosomes will be needed.

show abstract

Section: Discussionmentioning

confidence: 99%

“…53 Additionally, a temporal laser pulse profile stretches owing to multiple scattering by the tissue. 54 This effect may shift the energy deposition shown in Figure 6 to a value at a longer pulse width. Future studies will consider the effects of the surrounding tissue on energy deposition in melanosomes.…”

Section: Studymentioning

confidence: 99%

Nonlinear absorption‐based analysis of energy deposition in melanosomes for 532‐nm short‐pulsed laser skin treatment

et al. 2023

View full text Add to dashboard Cite

show abstract

“…In estimating the optical properties of a sample by combining IS and MC, one technique [28][29][30][31][32][33][34][35][36][37][38][39][40][41][42] that is often used is to measure the diffuse reflected light (backscattered light) and total transmitted light (forward scattered light and transmitted light) of a sample by IS and link the measured results with the absorption coefficient, scattering coefficient, and anisotropy coefficient by MC.…”

Section: Setupmentioning

confidence: 99%

“…On the other hand, disadvantages of the method include the loss of side scattering light and an inability to measure reflection and transmission under the same conditions because the reflected light and transmitted light are measured with a different IS [38]. SIS is a technique for measuring total transmittance by placing a sample at the entrance of the IS; diffuse reflectance is measured by placing a sample at the diffuse reflectance measurement port (the opening opposite the entrance) of the IS [35][36][37][38][39][40][41][42]. Since only one IS is used, the reflected light and transmitted light can be measured under the same conditions.…”

Section: Setupmentioning

confidence: 99%

Reproduction of Visible Absorbance Spectra of Highly Scattering Suspensions within an Integrating Sphere by Monte Carlo Simulation

Mori

Tokunaga

2023

Photonics

View full text Add to dashboard Cite

It is important to avoid the overestimation of absorption due to scattering when using absorption spectroscopy to measure scattering samples. We approached this issue by placing the sample inside an integrating sphere (IS) to collect the scattered light in all solid angles but encountered difficulty when determining the absorption coefficient from the absorbance because the light took various paths inside the IS and the sample. Therefore, by ray tracing inside the IS and the sample using Monte Carlo simulations (MC), we estimated the relationship between the absorption, scattering, anisotropy coefficients, and the measured absorbance. Scattering sample M, prepared by mixing polystyrene microspheres with trypan blue solution, and pure trypan blue solution for comparison were used as samples at various concentrations. MC reproduced the measurement results for the absorbance spectrum and its concentration dependence at 591 nm up to the measurement limit value. In addition, the saturated absorbance of sample M was lower than that of the trypan blue solution. This is because, from the distribution of distance d, light passed through the sample estimated by the MC, and more light with smaller d was detected due to scattering for higher concentration, resulting in a smaller increase in absorbance with the absorption coefficient.

show abstract

“…1.3 Esferas IntegradorasDiversos trabalhos que fizeram uso de esferas integradoras para determinar as propriedades ópticas de phantoms que simulam tecidos biológicos e amostras biológicas foram publicados nos últimos anos[4,20,21,22,23,24]. Os valores de refletância e transmitância são obtidos a partir de medidas empregando uma ou duas esferas integradoras e os coeficientes são calculados por um algoritmo.Uma esfera integradora é uma esfera oca com um revestimento altamente reflexivo em sua superfície interna (geralmente utiliza-se politetrafluoretileno ou Sulfato de bário (BaSO 4 )) para distribuir homogeneamente a luz que se propaga em seu interior.…”

unclassified

Determinação das propriedades ópticas de materiais altamente espalhadores

Fernandes¹

View full text Add to dashboard Cite

À Deus, por me capacitar a cada dia e me fazer superar medos e limitações. Por me conduzir com amor e realizar em minha vida mais do que sonhei. Eu te amarei, Senhor, fortaleza minha! Aos meus pais, Francisco e Maria das Graças, por todo amor, incentivo e inúmeras orações. Sem dúvidas, vocês foram minha motivação e força em todos os momentos. Cada cuidado de vocês me trouxeram até aqui! Vocês me mostraram o meu caminho. Obrigada por tudo! Ao meu amor, Guilherme, que com toda paciência e amor desde a graduação tem me ajudado de muitas formas. Obrigada pela cumplicidade e por acreditar em mim. Sem você seria muito mais difícil chegar até aqui. Amo você! À minha irmã, Jesuany, pelo apoio, incentivo e amizade. Nossa parceria é para toda a vida! Aos meus pais-de-lei, Marcelo e Elisangela, muito obrigada por sempre ter palavras de encorajamento e cuidar de mim. À toda minha querida e amada família pelas orações e apoio, saibam que levo cada um de vocês no meu coração. Ao Prof. Dr. Luciano Bachmann, pela oportunidade de desenvolver trabalhos científicos desde o primeiro ano da graduação e me aceitar como aluna de mestrado. Agradeço pela paciência em me ensinar e sempre ter ótimos conselhos práticos. Os conhecimentos transmitidos por você não ficaram limitados à ciência! Aos amigos da FAMB Miriã, Raquel, Bassam e todos meus amigos que perto ou longe estavam na torcida e me ajudaram nessa caminhada. Vocês fazem a minha vida mais feliz! Aos amigos do laboratório e grupo de fotobiofísica, aos amigos e veteranos Euclydes e Fabrício, muito obrigada por todo conhecimento partilhado e pela amizade. iv v Aos funcionários e técnicos do Departamento de Física, pela disposição em me auxiliar sempre que solicitado e pela qualidade do serviço prestado. À Capes, pela bolsa concedida.

show abstract

Study of the effect introduced by an integrating sphere on the temporal profile characterization of short laser pulses propagating through a turbid medium

Cited by 3 publications

References 24 publications

Nonlinear absorption‐based analysis of energy deposition in melanosomes for 532‐nm short‐pulsed laser skin treatment

Nonlinear absorption‐based analysis of energy deposition in melanosomes for 532‐nm short‐pulsed laser skin treatment

Reproduction of Visible Absorbance Spectra of Highly Scattering Suspensions within an Integrating Sphere by Monte Carlo Simulation

Determinação das propriedades ópticas de materiais altamente espalhadores

Contact Info

Product

Resources

About