Early diagnosis of teeth erosion using polarized laser speckle imaging

Nader, Christelle Abou; Pellen, Fabrice; Loutfi, Hadi; Mansour, Rassoul; Jeune, Bernard; Brun, Guy Le; Abboud, Maher

doi:10.1117/1.jbo.21.7.071103

Cited by 21 publications

(5 citation statements)

References 23 publications

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“…Hence, when the spatial (by using thin layer of colloidal QDs film) and spectral (by controlling the geometry of Ag NPs) overlap between LSP resonance and exciton is satisfied, ellipsoidal Ag NPs is one of the good candidates of scatter centers that can serve multiple functions of lowering threshold, providing strong scattering and causing optical anisotropy. As a result, it is believed that the newly developed random laser with coherent and polarized emissions can explore and broaden the applications in the related fields of optical modulator, display technology, and medical diagnosis …”

Section: Introductionmentioning

confidence: 99%

Coherent and Polarized Random Laser Emissions from Colloidal CdSe/ZnS Quantum Dots Plasmonically Coupled to Ellipsoidal Ag Nanoparticles

Yao

Yang

Hwang

et al. 2016

Advanced Optical Materials

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primarily due to the QD's high quantum yield, size-dependent spectral tunability, and environmental and temperature stability. Theoretically, the nanosized geometry (generally core sizes ≤10 nm) of QDs can provide 3D quantum confinement for charge carriers; however, such strong overlap of carrier wave functions may inevitably evoke undesired nonradiative recombination processes under a high injection of carriers. [16][17][18][19] A considerable carrier loss for the QDs as gain mediums will arise when compared to their counterpart semiconductors of bulk or higher dimensionality, which intrinsically constrains the required population inversion for achieving optical gain and, consequently, hinders the stimulated emissions based on the colloidal QDs. As a result, most of the previously mentioned applications are mainly focused on the QD's spontaneous emissions, and only a few demonstrations of optical gain and laser action related to the colloidal QDs are reported. [20][21][22][23][24] Among them, stimulated emissions from the colloidal QDs are mainly observed under excitation by intense, pulsed laser. Recently, the colloidal quantum wells structures are reported to suppress Auger recombination and achieve high-saturated gain, [25,26] which leads to a much lower threshold of pulsed pump fluence (6 µJ cm −2 ) than the typical values obtained in the colloidal QDs systems, as well as optically pumped in This study demonstrates the capability of controlling optical anisotropy of lasing emissions by manipulating the coupling strength spatially and spectrally between the oscillated electric field of emitted light and the localized surface plasmon (LSP) resonance for a random lasing medium composed of colloidal CdSe/ZnS quantum dots (QDs) and ellipsoidal silver nanoparticles (Ag NPs). Distinctive from the amplified spontaneous emission generally observed on colloidal CdSe/ZnS QDs, it has been found that lasing emissions of the revealed system exhibit clear interference features (coherent optical feedbacks) with low-threshold characteristics, mainly attributed to enhanced light scatterings and optical gains arisen in peripheral surfaces of ellipsoidal Ag NPs. Importantly, the relative orientation, between the oscillated electric field of emitted light from colloidal CdSe/ZnS QDs and the ellipse axis of Ag NPs, plays a critical role in selective excitation of LSP resonances leading to laser emissions with preferential optical polarizations.

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Section: Introductionmentioning

confidence: 99%

Coherent and Polarized Random Laser Emissions from Colloidal CdSe/ZnS Quantum Dots Plasmonically Coupled to Ellipsoidal Ag Nanoparticles

Yao

Yang

Hwang

et al. 2016

Advanced Optical Materials

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“…Such a map may be useful in classifying teeth as healthy or decayed upon co-linear and cross-circular measurement. Additional parameters can be incorporated to improve classification accuracy, such as speckle-based metrics, which have shown promise in tooth decay detection 73 – 75 and can be measured in a polarimetric setup 76 , 77 . Finally, it appears that the points form a somewhat straight line and their positions may be dependent on surface roughness (e.g., smoother surfaces yield higher x,y values), possibly enabling a calibration line to grade severity of tooth decay.…”

Section: Polarimetric Spatial Field Selection: Differentiating Normal...mentioning

confidence: 99%

Spatial analysis of polarimetric images to enhance near-surface sampling sensitivity: feasibility in demineralized teeth and other tissue-like media

Singh,

Lilge,

Vitkin

2023

J. Biomed. Opt.

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.SignificanceEarly tooth demineralization may be detectable through spatial analysis of polarized light images as demonstrated in this study. This may also prove useful in the early detection of epithelial tumors that comprise the majority of the cancer burden worldwide.AimThe spatial properties of polarized light images have not been greatly exploited in biomedicine to improve sensitivity to superficial tissue regions; therefore, we investigate the optical sampling depth effects as a function of location in the backscattered polarimetric images.ApproachBackscattered linear polarization intensity distributions exhibit four-lobed patterns arising through single-scattering, multiple-scattering, and geometrical effects. These photon pathway dynamics are investigated through experimental imaging of microsphere suspensions along with corroborative computational polarization-sensitive Monte Carlo modeling. The studied sampling depth effects of linear and circular polarization images (explored in a previous study) are then evaluated on normal and demineralized human teeth, which are known to differ in their surface and sub-surface structures.ResultsBackscattered linear polarization images exhibit enhanced sensitivity to near-surface properties of media (for example, surface roughness and turbidity) at specific locations within the four-lobed patterns. This yields improved differentiation of two tooth types when spatially selecting image regions in the direction perpendicular to the incident linear polarization vector. Circular polarimetric imaging also yields improved differentiation through spatial selection of regions close to the site of illumination. Improved sensitivity to superficial tissues is achieved through a combination of these linear and circular polarimetric imaging approaches.ConclusionsHeightened sampling sensitivity to tissue microstructure in the surface/near-surface region of turbid tissue-like media and dental tissue is achieved through a judicious spatial selection of specific regions in the resultant co-linear and cross-circular backscattered polarimetric images.

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“…M Z Ansari 1 , L C da Silva 2 , J V P da Silva 2 and A M Deana 2 erosion [6][7][8]. Recently Deana et al [8] have used it as a tool for assessing early carious lesions.…”

Section: Modelling Laser Speckle Photographs Of Decayed Teeth By Appl...mentioning

confidence: 99%

Modelling laser speckle photographs of decayed teeth by applying a digital image information technique

Ansari

Silva

et al. 2016

Laser Phys.

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We report on the application of a digital image model to assess early carious lesions on teeth. When decay is in its early stages, the lesions were illuminated with a laser and the laser speckle images were obtained. Due to the differences in the optical properties between healthy and carious tissue, both regions produced different scatter patterns. The digital image information technique allowed us to produce colour-coded 3D surface plots of the intensity information in the speckle images, where the height (on the z-axis) and the colour in the rendering correlate with the intensity of a pixel in the image. The quantitative changes in colour component density enhance the contrast between the decayed and sound tissue, and visualization of the carious lesions become significantly evident. Therefore, the proposed technique may be adopted in the early diagnosis of carious lesions.

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Early diagnosis of teeth erosion using polarized laser speckle imaging

Cited by 21 publications

References 23 publications

Coherent and Polarized Random Laser Emissions from Colloidal CdSe/ZnS Quantum Dots Plasmonically Coupled to Ellipsoidal Ag Nanoparticles

Coherent and Polarized Random Laser Emissions from Colloidal CdSe/ZnS Quantum Dots Plasmonically Coupled to Ellipsoidal Ag Nanoparticles

Spatial analysis of polarimetric images to enhance near-surface sampling sensitivity: feasibility in demineralized teeth and other tissue-like media

Modelling laser speckle photographs of decayed teeth by applying a digital image information technique

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