The Study Of Biological Tissue Hyperspectral Imaging Technology Based On Cascade Acousto-optic Filter

The spectral imaging technology with spatial resolution and spectral resolution is widely used in many fields.The acousto-optic Tunable Filter(AOTF)is a new type of light dispersion device,which has many advantages such as big incident angle,high diffraction efficiency,quick scanning speed,wide tuning range and so on.The spectral imaging based on AOTF has gradually become one of the hot spots of optics in the world.The spectral resolution is an important performance index of non-collinear acoustic-optic tunable filter,which directly determines the ability of recognition and detection for the target.Exploring an effective method of the spectral resolution improvement.,and using it in the spectral imaging,has certain scientific significance and application value.Considering the limitations of improving the spectral resolution by optimizing the production process of the AOTF,a design for increasing the spectral resolution by using cascaded acousto-optic filtering is proposed.The variation law of secondary filter spectral width with ultrasonic frequency difference is obtained.And the spectral resolution performance and diffraction efficiency are taken into account simultaneously.A method of choosing the proper ultrasonic frequency difference around the equilibrium point is established.A cascaded acousto-optic filter microscopic spectral imaging system is constructed.In the visible light range,a large number of spectral images about resolution test target and non-stained gastric cancer tissue are obtained.The spectral bandwidth is narrow and the microscopic images are clear.The study confirms that the cascade filtering method can improve the spectral resolution performance of the system by comparing the images of double-filtering with single-filtering.The detailed structure of the non-stained gastric cancer tissue can be accurately identified in the wavelength range of 507.82 nm to 565.05 nm.It indicates that the established system can provide technical support for rapid and non-destructive diagnosis of biomedicine.In order to improve the portability of the spectral imaging system,an optical fiber acousto-optic filtering spectral imaging device is preliminarily established.The spectral resolution and image resolution of the resolution test target are well in the range of 467.54 nm-705.85 nm.It reflects the effectiveness of the spectral imaging based on the AOTF and the optical fiber imaging bundle.This study provides a new idea for the development and application of the acousto-optic filtering spectral imaging.