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

1.利用自调制效应产生了一个倍频程以上（460-1060 nm）的超宽带光脉冲。它是光谱相位补偿和其特征在于是一个2.8 fs，1.5周期傅立叶变换限制脉冲的修改后的光谱相位干涉直接电场重建。它是最短的可见光和红外脉冲，其光谱相位是确定的。2.二次谐波激光显微镜的三维空间分辨观察的活细胞。作为一个例子，观察大鼠的神经元。强烈的信号，从核和轴突由于反转对称性破缺被检测到。空间分辨率小于1.5 μ m。3.以飞秒激光放大器为光源，研制了相干反斯托克斯拉曼散射激光显微镜。对于洋葱细胞，采用波长为800和1040 nm的两个脉冲来激发2900 cm-1的C-H振动模式，并检测到波长为650 nm的相应空间分辨信号。同样，采用波长为800和1100 nm的两个脉冲激发3400 cm-1的N-H振动模式，并检测到波长为630 nm的相应信号。通过比较这些信号，确定了细胞中富含C-H和N-H的结构域。4.用二次谐波激光显微镜对甲基红嵌入DNA的杂交和去杂交进行了宏观观察。而杂化分子具有反转对称性，去杂化分子则不具有反转对称性。由于噪声，迄今为止没有获得显著的信号。通过引入其他具有更高光学非线性的偶氮染料进行改进。

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.