Research On Active Sensing Mechanism Based On Surface Slot Structur

According to grating theory,there are a series of speckle patterns in the surface optical field of the high-order grating semiconductor laser.In order to achieve the purpose of sensing,we deliberately amplify the variation of speckle quantity and intensity and design a sensor based on a random slot semiconductor laser.The light generated by the sensor itself can sense changes in the outside world and form feedback to influence light generation.By detecting this change,we can learn about the substance’s changes.Specifically,we simulated the refractive index sensor,the erythrocytes flow velocity sensor,and the erythrocytes concentration sensor.On the one hand,the refractive index is a physical parameter closely related to temperature,concentration,material and so on.It is widely used in physics,biology,chemistry,medicine,food safety and other fields.On the other hand,the capillary blood flow velocity is fast,which is not conducive to the material exchange between blood and tissue cells.When the number of erythrocytes decreases,the body’s hemoglobin concentration drops,causing symptoms of anemia.This novel random slot semiconductor laser presents a new biosensor scheme,provides a new flexible platform for multifunctional active sensing,and has a wide application prospect in the field of sensing in the future.This paper mainly designs the structure of the random slot semiconductor laser.On the one hand,it simulates the refractive index sensor,the erythrocytes velocity sensor and the erythrocytes concentration sensor.On the other hand,it optimizes the direction and decoupling efficiency of the random semiconductor laser.The specific research content and structure are as follows:(1)A novel random slot semiconductor laser is designed.According to the advantages and disadvantages of distributed feedback(DFB)semiconductor laser,distributed Bragg(DBR)semiconductor laser,horizontal cavity surface emission distributed feedback(SE-DFB)semiconductor laser,high order grating semiconductor laser and other grating semiconductor lasers,the random slot semiconductor laser is designed based on the special requirements of sensors.The width and spacing of the slots are greater than 1μm,and the light emitted from the laser surface forms a series of distinct random speckle patterns.(2)Based on random slot semiconductor laser,we propose a refractive index sensor scheme.The refractive index sensor based on a random slot semiconductor laser is established by the finite element method.At single wavelength lasing,light emitted from the surface has different optical path differences when passing through substances with various refractive index,resulting in different far-field intensity peaks.We extract the peak intensity to judge the refractive index,and compare the performance of different types of lasers.At multiple wavelengths lasing,we use the finite-difference time-domain method to establish the same physical field,and extract the sum of the intensity of the laser surface emission.The refractive index of the substance is determined by the similarity curve of the sum of intensity.(3)Based on the random slot semiconductor laser,we propose the erythrocytes flow rate sensor and the erythrocytes concentration sensor.Using a similar principle,we study the erythrocytes flow rate sensor in capillary based on a random slot semiconductor laser at single wavelength lasing.In addition,we propose another sensing strategy to measure the flow velocity of erythrocytes.The displacement of erythrocytes can be determined by the similarity curve of intensity contrast.At multiple wavelengths lasing,the similarity of intensity can also be used to judge the flow velocity of erythrocytes by the finite element method.Additionally,the similarity of the spectral contrast at multiple wavelengths lasing can be used to determine the concentration of erythrocytes in capillaries.(4)We optimize the directivity and decoupling efficiency of the random slot semiconductor laser.The directivity of a semiconductor laser with 7 random slots is optimized by BP neural grid based on the improved whale algorithm and genetic algorithm.Firstly,the grid relationship between the 13 variables and the target parameters(the full width at half maximum on the laser surface)is established.Secondly,the full width at half maximum and corresponding structural parameters are obtained through the operation of genetic algorithm,such as heredity,variation and crossover.Finally,the performance of the optimized refractive index sensor was verified by finite element method.In addition,we improve the decoupling efficiency of the random slot semiconductor laser by optimizing the slot depth and the dip Angle of the side wall.