为得到高准确度的小球藻浓度,利用空芯金属包覆波导作为测量腔对小球藻进行测量.利用自由空间耦合技术激发含有小球藻溶液的空芯金属包覆波导中超高阶导模，通过检测超高阶导模的衰减全反射吸收峰位置和反射极小值Rmin的变化，实现了小球藻溶液浓度和吸收系数的同时测量.该方法不仅可检测10－9 mol量级的小球藻浓度，而且具有测量成本低、操作方便等优点.

To achieve high accuracy of chlorella concentration measurement, using the hollowcore metalcladding waveguide as the measuring chamber for cholrella measurement. Ultrahigh order modes was excited to detect the concentration of chlorella with the free space coupling technique，by monitoring the position and the reflection minimum Rmin of the attenuated total reflection peak of ultrahigh order mode, the concentrations and the absorption coefficients of chlorella solution for the different light wavelength were simultaneously detected. The novel technique is not only achieving detection to 10－9 mol chlorella solution, but also have the advantages of low measuring cost and easy operation, etc.