A spatial frequency domain imaging system (SFDI) was developed to estimate the optical properties of biological samples. The system was calibrated by using a series of self-made solid phantoms which covering a wide range of absorption ( µ
a
) and reduced scattering coefficients ( \({\mu ^{\prime}_s}\) ). The relative errors between the reference and calibrated values were regarded as the evaluation parameters for validation effectiveness of the system, the results showed that the maximum relative errors of µ
a
and \({\mu ^{\prime}_s}\) are 3.92 and 2.39% respectively. Quantitative absorption and scattering maps at the wavelength of 527 nm were obtained for four kinds of pear samples (normal and bruised with three levels of bruised severity with impact energy of 0.025, 0.075 and 0.125 J). The normal pears could be distinguished from the bruised pears by comparing values of coefficient of variation ( CV ) of \({\mu ^{\prime}_s}\) maps, and the correct rates of the discriminant analysis were 100% for non-bruised pears,and 98.33% for bruised pears. Bruises induced using 0.025 J (class 1) were distinguishable from those induced using 0.075 and 0.125 J (class 2) by comparing ratio between mean values of bruised region and normal region of \({\mu ^{\prime}_s}\) maps, the results turned out that the class 1 had the correct rate of 90%, and class 2 had the correct rate of 87.5%. The research showed that SFDI has the potential to be used in the detection of bruises on ‘Crown’ pears and the proposed calibration method lay the foundation for future studies. Future work will be conducted with an emphasis on the acquisition of more spectral information, surface profile correction and the acceleration of detection speed.
Surface plasmon coupled emission (SPCE), a novel surface-enhanced fluorescence technique, can generate directional and amplified radiation by the intense interaction between fluorophores and surface plasmons (SPs) of metallic nanofilms . For plasmon-based optical systems, the strong interaction between localized and propagating SPs and “hot spot” structures show great potential to significantly improve the electromagnetic (EM) field and modulate optical properties . Au nanobipyramids (NBPs) with two sharp apexes to enhance and restrict the EM field were introduced through electrostatic adsorption to achieve a mediated fluorescence system, and the emission signal enhancement was realized by factors over 60 compared with the normal SPCE. It has been demonstrated that the intense EM field produced by the NBPs assembly is what triggered the unique enhancement of SPCE by Au NBPs, which effectively overcomes the inherent signal quenching of SPCE for ultrathin sample detection. This remarkable enhanced strategy offers the chance to improve the detection sensitivity for plasmon-based biosensing and detection systems, and expand the range of applications for SPCE in bioimaging with more comprehensive and detailed information acquisition. The enhancement efficiency for various emission wavelengths was investigated in light of the wavelength resolution of SPCE, and it was discovered that enhanced emission for multi-wavelength could be successfully detected through the different emission angles due to the angular displacement caused by wavelength change. Benefit from this, the Au NBP modulated SPCE system was employed for multi-wavelength simultaneous enhancement detection under a single collection angle, which could broaden the application of SPCE in simultaneous sensing and imaging for multi-analytes, and expected to be used for high throughput detection of multi-component analysis.
危险品化学品经营许可证（带存储）