Development of UV excitation CARS microscopy system and applications to biological tissue measurement

我们利用两个同步的ps-Ti: Sapphire激光器开发了一个多焦点CARS显微镜系统。CARS显微镜需要两种不同波长的激光器，峰值强度高，光谱带宽在几cm^<-1>左右，波长扫描范围在2000cm^<-1>左右。因此，我们开发了一个使用两个同步ps-Ti：蓝宝石激光器作为光源的系统。采用微透镜阵列对平行点进行激发和观测，缩短了测量时间。激光的二次谐波也可用于电共振增强。对于没有近红外和紫外吸收的聚苯乙烯珠，由于紫外光束强度低，仅通过近红外激发获得CARS光谱和图像。另一方面，对于吸收在400 nm左右的人红细胞，由于电共振增强，紫外激发可获得清晰的CARS光谱和图像。结果证实了电共振增强对CARS显微成像的重要性。

We developed a multi-focus CARS microscopy system using two synchronized ps-Ti : Sapphire lasers. CARS microscope require two lasers with different wavelength, high peek intensity, narrow spectral bandwidth around a few cm^<-1>, and large wavelength scanning range about 2000cm^<-1>. Therefore, we developed a system using two synchronized ps-Ti : Sapphire lasers for light source. A micro-lens array is used to excite and observe parallel points for shortening the measurement time. The second harmonics of lasers are also available to use for electric resonance enhancement.For the polystyrene beads without absorption at near-IR and UV, the CARS spectrum and image are obtained by near-IR excitation only, because of low intensities of UV beam. On the other hand for human erythrocyte which has absorption around 400 nm, Clear CARS spectrum and image are obtained by UV excitation, because of electric resonance enhancement.As the results, it was confirmed that the electric resonance enhancement is the important for CARS microscopy.