| 摘要 |
PURPOSE:To achieve a positioning between a focus position of a laser irradiation light and a flow position of fine particles handily and accurately, by running fine particles comprising a non-linear optical medium into a flowcell to detect intensity of light with a converted wavelength as generated by irradiation with laser. CONSTITUTION:Fine particles flow into a passage section 2 of a flowcell 1 and irradiated with a laser beam L through an imaging lens 4 from a laser light source 3. Consequently, the laser beam L is converted partially into lambda/2 in wavelength by SHG effect according to a conversion efficiency to be transmitted through the fine particle and the rest thereof pass with the wave length of lambda as intact free from conversion. Light with a wavelength of lambda/2 alone is extracted with a barrier filter 6 to be received with a photo detector 9 through an objective lens 7 and a condenser lens 8 and an output thereof is inputted into a positioning circuit 30. A feedback control is performed with the positioning circuit 30 so that the light detected with the photo detector 9 becomes the highest in intensity. Thus, an optical stage 10 is moved with a flowcell 1 fixed thereon. |
