声光可调谐滤波器的细胞生物学研究应用

波长选择在荧光光谱仪和显微镜等光学应用中发挥了至关重要的作用。声光可调谐滤波器(AOTF)作为一种电光器件可实现多光源入射波长、功率的同时调制。在声光可调谐滤波器中,压电换能器结合于二氧化碲或石英晶体产生高频声波,改变晶体折射率形成周期性分布。该现象在晶体中生成衍射光栅,使以布拉格角正交入射的光束被高效衍射至一阶光束。当改变施加到晶体的信号频率时将改变折射率变化周期,因此,衍射光的波长随之改变。同时,衍射光强度由施加到晶体的信号振幅决定。本文从声光可调谐滤波器原理和特点出发,总结了声光可调谐滤波器在细胞生物学研究系统中的应用模型。得益于作用时间短、波长分辨率高、无振动部件等特性,声光可调谐滤波器提升了多波长光源功率调制能力,使细胞计数系统具备了细胞高光谱成像能力。所以不仅限于传统细胞生物学研究,包含声光可调谐滤波器件的系统还将在多参数高内涵成像分析、扫描荧光显微术、药物毒理研究等领域成为有力的研究工具。

Application of Acousto-optic Tunable Filter in Cell Biology

Wavelength selection is of great importance in many areas of optical science, including fluorescence spectroscopy and microscopy. Acousto-optic tunable filter (AOTF) is an electro-optical device which can modulate intensity and wavelength of multiple optical sources simultaneously. In an acousto-optic tunable filter, a piezoelectric transducer bonded to a crystal of tellurium dioxide or quartz generates high-frequency acoustic waves to alter the refraction of crystal in a periodic pattern. This phenomenon leads to the generation of a diffracted grating so that an orthogonal beam incident at the Bragg angle is diffracted with high efficiency into the first order beam. With change of signal frequency applied to the crystal, the period of the refraction variation alters, and therefore, the wavelength of diffracted beamchanged. The intensity of the diffracted beamis determined by the amplitude (power) of the signal applied to the crystal. In this review, the theory and the characteristics of AOTF are presented. The application models in cell biology research systems are summarized. Benefiting from many advantages such as short interaction time, high spectral resolution and free of vibrational components, the acousto-optic tunable filters were used to enhance the modulation capabilities in multi-wavelength light sources and get hyperspectral images in cell count systems. In the future, the systems which include AOTFs will become invaluable tools not only for classical cell biological research but also for emerging technologies like multiparameter high-content image analysis, scanning fluorescence microscopy and drug toxicology and others.