用光学参数定量诊断病变组织是当前生物医学光子学领域中研究的热点问题。利用太赫兹时域光谱系统,在室温氮气环境中,获得了不同质量分数无水葡萄糖在0.15~3THz频段的高分辨率吸收谱和折射率谱;基于密度泛函理论,利用Gaussian09软件对葡萄糖进行了B3LYP/6—31G水平上的单分子、双分子和多分子结构优化和红外吸收模拟;基于MaterialsStudio7.0量子化学计算软件,采用CASTEP模块和广义梯度近似方法,开展了对葡萄糖晶体结构的频率计算。实验结果表明,葡萄糖在0.94,1.30,1.44,1.67,1.88,2.08,2.31,2.55,2.70,2.84,2.96THz有吸收峰,所有峰位的强度随样品中葡萄糖质量分数的增加线性降低;Gaussian09模拟结果与测试结果相吻合,CASTEP的结果验证了这一结论;对无水葡萄糖在太赫兹频段的吸收峰进行了全面指认和振动归属。研究结果为太赫兹时域光谱在生物医学方面的应用提供了实验及理论参考。
In biomedical photonics, it's extraordinarily significant to diagnose lesion by quantificational optical parameters. The high resolution absorption and refractive index spectra of samples with different mass fractions of anhydrous glucose are acquired by terahertz time-domain spectroscopy system in nitrogen atmosphere at room temperature. The characteristic absorption is analyzed based on the density functional theory. Gaussian 09 is used to simulate the optimized structure and infrared spectroscopy of single, double, triple and quadruple glucose molecules. Meanwhile, the B3LYP method and 6-31G basis set are adopted. In addition, Materials Studio 7.0 is utilized to calculate the frequency generated by the glucose crystal structure, which is completed with the help of CASTEP module and the generalized gradient approximation method. The experimental results show that the absorption peaks of anhydrous glucose appear at0.94, 1.30, 1.44, 1.67, 1.88, 2.08, 2.31, 2.55, 2.70, 2.84, 2.96 THz, and the intensities of all peaks decrease linearly with the increase of glucose mass fraction in samples. The results of Gaussian 09 are in agreement with the test results, which is verified by the results of CASTEP. The absorption peaks of anhydrous glucose are identified accurately in the range of terahertz waveband. The reuslts provide experimental and theoretical reference for the application of terahertz time-domain spectroscopy in biomedicine.