DNA 薄膜水合作用的光学三次谐波产生研究。
Optical third harmonic generation study of the hydration of DNA films.
作者信息
Szabó A, Wang Y, Lee S A, Simon H J, Rupprecht A
机构信息
Department of Physics & Astronomy, University of Toledo, Ohio 43606-3390.
出版信息
Biophys J. 1993 Dec;65(6):2656-60. doi: 10.1016/S0006-3495(93)81307-9.
Optical third harmonic generation (THG) has been observed for the first time from DNA films. The THG signal is observed from NaDNA films exposed to relative humidities (RHs) between 0% and 98%. A strong enhancement (approximately 5x) of the THG signal from NaDNA is observed at 84% RH; no enhancement is observed for RbDNA. The most likely mechanism for such an enhancement is an increased coherence length. A model calculation using estimates of the refractive indices at both the fundamental and third harmonic frequencies supports this interpretation. The observed THG signal has the same polarization as the incident (fundamental) light. For the A conformation, the THG signal polarized perpendicular to the helical axis is approximately twice as strong as the signal polarized parallel to the helical axis. No such anisotropy is observed for either the disordered conformation (below about 50% RH) or the B conformation (above 92% RH).
首次在DNA薄膜中观察到光学三次谐波产生（THG）。在暴露于0%至98%相对湿度（RH）的NaDNA薄膜中观察到THG信号。在84%相对湿度下观察到NaDNA的THG信号有强烈增强（约5倍）；RbDNA未观察到增强。这种增强最可能的机制是相干长度增加。使用基频和三次谐波频率处折射率估计值的模型计算支持这一解释。观察到的THG信号与入射（基频）光具有相同的偏振。对于A构象，垂直于螺旋轴偏振的THG信号强度约为平行于螺旋轴偏振信号的两倍。对于无序构象（相对湿度低于约50%）或B构象（相对湿度高于92%）均未观察到这种各向异性。
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