Figure 2From: Study of probe-sample distance for biomedical spectra measurement Collection efficiency of single fiber probes with a core-diameter of 50, 100, 200 and 500 μm at normal illumination (a) and collection efficiency of single fiber probes with core-diameter of 200 μm at different illumination angles (b). In the above calculation, the fiber NA = 0.22 was used.Back to article page