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We propose a scheme that can generate tunable magnomechanically induced amplification in a double-cavity parity-time-(PT -) symmetric-like magnomechanical system under a strong control and weak probe field. The system consists of a ferromagnetic-material yttrium iron garnet (YIG) sphere placed in a passive microwave cavity which is connected with another active cavity. We reveal that ideally induced amplification of the microwave probe signal may reach the maximum value 1000000 when cavity-cavity, cavity-magnon and magnomechanical coupling strengths are nonzero simultaneously. The phenomenon might have potential applications in the field of quantum information processing and quantum optical devices. Besides, we also find the phenomena of slow-light propagation. In this case, group speed delay of the light can achieve 0.000035s, which can enhance some nonlinear effect. Moreover, due to the relatively flat dispersion curve, the proposal may be applied to sensitive optical switches, which plays an important role in storing photons and quantum optical chips., 6 pages,6 figures

In this contribution, surface-enhanced Raman spectroscopy (SERS) coupled with an advanced chemometric method-multiplicative effects model (MEM SERS ) has been applied to quantitative analysis of ametryn in water samples of the Xiangjiang River (Changsha, China). The adoption of MEM SERS calibration model was to eliminate the detrimental effects caused by variations in the physical properties of enhancing substrates, the intensity and alignment/focusing of laser excitation source. Experimental results showed that the combination of SERS with MEM SERS can provide quite precise concentration predictions for ametryn in water samples of the Xiangjiang River with an average relative prediction error of about 4.8%. The combination of SERS with MEM SERS can compete with LC-MS/MS in terms of precision and accuracy of quantitative results. The limit of quantification was about 0.09 μM. More importantly, no laborious reference methods (e.g., HPLC) were needed to build the MEM SERS calibration model, since the MEM SERS calibration model built on the calibration samples prepared with ultrapure water could provide satisfactory quantification results for the test samples prepared with water collected from the Xiangjiang River. Therefore, it is reasonable to expect that SERS in combination with MEM SERS model would become a competitive alternative in routine quantitative analysis of ametryn in environmental water samples.

Surface-enhanced Raman spectroscopy (SERS) is a leading non-destructive technique with single-molecule sensitivity and has great potential for application in various fields. However, quantitative analysis of analytes using SERS is still quite challenging, since SERS signals are significantly affected by the physical properties of SERS enhancing substrates. Here, we report the detection of rhodamine 6G (R6G) and thiram (a dithiocarbamate fungicide) by SERS technique through the combination of a recently proposed multiplicative effects model (MEM) and magnetic nanoparticles (i.e. Fe 3 O 4 @Au and Fe 3 O 4 @Ag). Experimental results showed that R6G and thiram can be accurately determined with average relative prediction error of 3.2% and 7.5%, respectively. It looks promising that SERS technique based on the combination of multiplicative effects model and magnetic nanoparticles can be applied to the quantitative assay of many other analytes.

The quantitative determination of analytes in plasma by dry film-based near infrared spectroscopy (NIR) is significantly affected by the thickness variations of dry films. Internal standards are generally used to enhance the reproducibility of quantitative results. However, it is difficult to select an appropriate internal standard with general applicability, and the introduction of an internal standard into plasma samples also complicates experimental procedures. In this work, a quantitative NIR transmission spectroscopy model was proposed to explicitly model the effects of the variations in thickness and light scattering characteristics of dry plasma films on NIR transmission measurements, and an advance dual calibration strategy based on support vector regression (DCS SVR ) was derived from the proposed quantitative model to realize accurate determination of analytes (e.g. glucose) in dried plasma samples without the use of internal standards. By using the dry film method coupled with the proposed technique, glucose in plasma could be determined over a concentration range of 0.4–20 mmol L − 1 with satisfactory accuracy (average relative predictive error less than 7.0%) while avoiding any use of internal standards. It can reasonably be expected that the DCS SVR strategy might be of major benefit for the quantitative NIR spectroscopic analysis of analytes of clinical significance in dried biofluid samples.

The presence of scatterers in turbid media could severely distort the Raman measurements and thereby prevent accurate determination of analytes in turbid media. To address this issue, in this contribution, an advanced model, multiplicative effects model (MEM), has been derived to explicitly model the effects of scatterers on Raman measurements. Preliminary experimental results for a proof of concept system with varying turbidity levels demonstrated that MEM could effectively account for the detrimental multiplicative effects of scatterers and ultimately achieved accurate quantitative analysis of analyte of interest in turbid media with a relative prediction error of about 4.3%. The enhanced levels of accuracy obtained with MEM open up an avenue for prospective prediction studies in turbid media such as biological tissues by Raman spectrometry.