Boustany N N
Appl Opt. 2001 Dec 1;40(34):6396-405. doi: 10.1364/ao.40.006396.
In contrast to spectroscopy at longer wavelengths, typical attributes of ultraviolet resonance Raman (UVRR) spectroscopy of biologic tissue are higher absorption coefficient, mu, and higher photobleaching rate, kappa. This study was aimed at measuring mu and kappa during UVRR spectroscopy of human colon tissue at 251 nm. mu was used to estimate the penetration depth of the excitation light; kappa was used to predict the rate of signal decrease that was due to photobleaching as a function of laser fluence and tissue thickness. The fitting of the equations through description of a three-state transition model to experimental data that consisted of a purine UVRR signal gave mu = 0.0169 ? 0.0023 mum(-1) and kappa = 0.572 ? 0.168 (mJ/mum(2))(-1). kappa remained independent of power P for P < 1 mW, but higher power values resulted in a higher photobleaching rate. As predicted by the model, signal decrease that was due to photobleaching was slower as sample thickness was increased.
与较长波长的光谱学相比，生物组织的紫外共振拉曼（UVRR）光谱的典型特征是具有更高的吸收系数μ和更高的光漂白速率κ。本研究旨在测量251nm下人体结肠组织UVRR光谱过程中的μ和κ。μ用于估计激发光的穿透深度；κ用于预测由于光漂白导致的信号下降速率，该速率是激光能量密度和组织厚度的函数。通过描述三态跃迁模型将方程拟合到由嘌呤UVRR信号组成的实验数据，得到μ = 0.0169 ± 0.0023μm⁻¹和κ = 0.572 ± 0.168（mJ/μm²）⁻¹。对于P < 1mW，κ与功率P无关，但更高的功率值会导致更高的光漂白速率。如模型所预测的，随着样品厚度增加，由于光漂白导致的信号下降更慢。
