Spatio-temporally resolved observation and control of neuron excitement mechanism using nonlinear laser microscopes

1.利用自调制效应产生超过一倍频程跨度（460 ~ 1060nm）的超宽带光脉冲。经光谱相位补偿，采用改进的光谱相位干涉法对其进行直接电场重建，表征为2.8 fs、1.5周期傅立叶变换受限脉冲。它是最短的可见和红外脉冲，光谱相位确定得很好。研制了用于三维空间分辨观察活细胞的二次谐波激光显微镜。以大鼠为例，对其神经元进行了观察。从核和轴突中检测到逆对称性破缺引起的强信号。空间分辨率小于1.5 μm.3。采用飞秒激光放大器作为光源，研制了一种相干反斯托克斯拉曼散射激光显微镜。以洋葱细胞为实验对象，采用波长为800 nm和1040 nm的两个脉冲激发2900 cm-1的C-H振动模式，检测到波长为650 nm的空间分辨信号。同样，利用波长为800 nm和1100 nm的两个脉冲激发3400 cm-1的N-H振动模式，检测到波长为630 nm的相应信号。通过对这些信号的比较，确定了细胞中c - h和n - h的富结构域。用二次谐波激光显微镜对甲基红插入DNA的杂交和去杂交进行宏观观察。杂化的具有逆对称性，去杂化的则没有。由于噪声的影响，到目前为止还没有获得重要的信号。通过引入其他具有更高光学非线性的偶氮染料，正在进行改进。

1.An over-one-octave spanning (460-1060 nm) ultra-broadband optical pulse was generated by self-modulation effect. It was spectrally-phase-compensated and characterized to be a 2.8 fs, 1.5 cycle-Fourier-transform-limited pulse by the modified spectral phase interferometry for direct electric-field reconstruction. It is the shortest visible and infrared pulse whose spectral phase is well determined.2.A second-harmonic laser microscope was developed for 3-dimensional spatially-resolved observation of living cells. As an example, neurons of a rat were observed. Strong signals from nuclei and axons owing to inversion-symmetry breaking were detected. Spatial resolution was less than 1.5 μm.3.A coherent anti-Stokes Raman scattering laser microscope was developed using a femtosecond laser amplifier as a light source. For onion cells, two pulses with wavelengths of 800 and 1040 nm were employed to excite the C-H vibration mode of 2900 cm-1 and the corresponding spatially-resolved signal with a wavelength of 650 nm was detected. Similarly, two pulses with wavelengths of 800 and 1100 nm were employed to excite the N-H vibration mode of 3400 cm-1 and the corresponding signal with a wavelength of 630 nm was detected. From comparison between those signals, C-H-and N-H-rich domains in cells were determined.4.Macroscopic observation of hybridization and dehybridization for methylred-intercalated DNA was performed using second-harmonic laser microscope. While hybridized one has the inversion symmetry, dehybridized one does not. Significant signals were not obtained so far because of noise. Improvement is going on by introducing other azo-dyes with higher optical nonlinearity.