In this brief review, nonlinear optical (NLO) chromophores widely used in electro-optic (EO) devices are summarized according to their EO coefficients. The advances of EO modulators based on organic materials in high bandwidth and low half wave voltages (V p ) are discussed. The review is mainly devoted to the following aspects: (1) verification of high frequency operation and reduction of V p for all polymer waveguide EO modulators; (2) structures and advantages of sol-gel waveguide EO modulators; (3) principles and developments of silicon-organic hybrid (SOH) EO modulators. All the considerations are illustrated by the architecture of the devices and the used physical and chemical principles are explained in detail. Further means of improvement of their parameters are indicated.
In this study, we developed a flexible and transparent silver/polystyrene/polydimethylsiloxane (Ag/PS/PDMS) substrate with both high density of hot spots and satisfactory uniformity using a cost-effective approach. Via template-guided self-assembly, PS beads were arranged regularly in nanobowls of a square array on PDMS, whose surface structure was transferred from a commercial CMOS chip. Roughness was introduced onto the PS bead surface by nitrogen plasma treatment, followed by sputtering of Ag which generated many hot spots. Differential roughness on the PS bead surface greatly influenced the morphology of the Ag/PS/PDMS substrate. A meat-ball like surface structure was formed with a plasma etching time of 5 min, whose growth mechanism was proposed based on the SEM analysis. The high sensitivity and desirable uniformity of the meat-ball like Ag/PS/PDMS substrate were demonstrated by using crystal violet (CV) as a Raman reporter, exhibiting an enhancement factor (EF) of 2.7×107 and a relative standard deviation (RSD) of 5.04%. Thiram of a lower concentration than the maximum residue limit (MRL) on the cucumber surface could easily be detected in-situ by the proposed substrate, demonstrating its great potential for in-situ food safety analysis.
Developing high-power electric-driven system is the key to realize green exploration of vibroseis. To improve the safety and extend the cycle life of the lithium-ion batteries for electric-driven vibroseis, two types of liquid-cooling structure for the battery pack were developed and evaluated. The thermal performance of the liquid-cooling structures was evaluated by three indexes of the maximum temperature in the whole battery pack, the maximum temperature difference between the cells, and the standard deviation (SD) coefficient of the cells' temperature. Results suggest that the maximum temperature difference and the SD coefficient of the single-inlet-single-outlet liquid-cooling structure is 7.43 C and 6.49%, respectively, and both fail to meet the indexes. In the double-inlet-double-outlet liquid-cooling structure, the maximum temperature increases linearly with the growth of the coolant inlet temperature. With higher coolant flow rate, the maximum temperature is lower, while the temperature difference between the two sides of the cell is greater. When the inlet temperature of the coolant is below 33.9 C and the coolant flow rate is greater than or equal to 350 g/s, the thermal performance evaluation indexes of the battery pack could be achieved. Field test of the electric-driven vibroseis shows that the double-inlet-double-outlet structure can fully achieve the cooling requirements. This research provides significant support for the development of green-exploration vibroseis.
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