Deblén H, Oberg P A
Department of Biomedical Engineering, Linköping University, Sweden.
Med Biol Eng Comput. 1991 Sep;29(5):470-4. doi: 10.1007/BF02442316.
Low-frequency noise in laser Doppler recordings can be generated because of thermal instabilities in the gas laser cavity. Mode partition noise can be eliminated by thermal stabilisation of the laser cavity. The paper describes a method for closed loop temperature control of the laser cavity. The method uses orthogonal properties of longitudinal laser modes for the temperature control. The signal-to-noise ratio is considerably improved by the procedure. It is recommended that all gas laser equipped Doppler instruments used for precision blood flow studies should be equipped with stabilised laser sources.
激光多普勒记录中的低频噪声可能是由于气体激光腔中的热不稳定性产生的。通过对激光腔进行热稳定化处理，可以消除模式分配噪声。本文描述了一种用于激光腔闭环温度控制的方法。该方法利用纵向激光模式的正交特性进行温度控制。通过该过程，信噪比得到了显著提高。建议所有用于精确血流研究的配备气体激光的多普勒仪器都应配备稳定的激光源。
