Effect Of Deformation Of Photoinduced Polymer On Holographic Sensing Performance

Sensor is an important measuring device in people's daily production and life.In recent years,photoinduced polymer as a kind of attractive holographic sensing material and optical element has attracted extensive attention.Holographic sensor is a new kind of sensor,which works by recording volume grating in photoinduced polymer.When external conditions change will lead to corresponding changes in the holographic optical properties,including stripe space and refractive index modulation holographic grating,the average refractive index and the grating diffraction spectrum peak wavelength and diffraction efficiency change,scale grating optical parameter change and external conditions change the relationship between the quantity of holographic sensor can be realized.This paper mainly studies the effect of deformation of photoinduced polymer on holographic sensing performance.A acrylamide photoinduced polymer holographic sensor based on flexible substrate was developed and its bending deformation characteristics were investigated.Three important deformation types are analyzed by volume grating diffraction spectrum: unilateral bending deformation,bilateral bending deformation and bilateral bending straightening deformation.When the sensor is bent on one side,the experimental results of reading grating with extended and non-extended light sources are given.There is little difference between the two tests.The maximum position sensitivity is up to 54.09 nm/mm,and the average angle sensitivity is 22.42 nm/deg.When sensing bilateral bending deformation,as a non-extended light source reading light can provide more accurate measurement results and higher sensitivity.Sensitivity up to 43.95 nm/mm(peak wavelength/radius of curvature).The rainbow diffraction spectrum can effectively reflect the bending deformation when characterizing the initial bilateral bending before straightening.In addition to studying the bending deformation of the holographic sensor,the stretchable acrylamide photoinduced polymer without substrate is also used to develop the holographic sensor and the spatial uniformity of its tensile deformation is studied.The diffraction spectrum with large area holographic grating as the main response parameter is scanned.The linear spatial distribution of peak wavelength provides an important basis for studying the tensile uniformity of polymer holographic sensor.The same ratio of wavelength to position confirms that the tensile deformation of the material is uniform within the small spot size.The main characteristic of tensile deformation uniformity is the gradual accumulation of deformation over the whole length range of materials.The tensile uniformity response can be used to detect the deformation and stress fluctuation distribution in the middle of thin material surface.The uniformity of tensile deformation was measured by optical method,which further confirmed the application of holographic sensor based on stretchable polymer.