Figure 1.

Power/fluence dependence of 785 nm excited Raman spectra of dried whole human blood. The Raman spectrum on top of the observed fluorescence as a function of incident laser power is shown in the inset. Spectral changes at 667, 747, 970 and 1248 cm⁻¹ are highlighted by vertical lines. The whole blood was stored at 8 °C for about 2 weeks before drying in the ambient for ~2 hours. The Raman illuminated area is 100 μm² corresponding to incident laser fluences of 1.9x10³ (1.9 mW), 3.5x10³ (3.5 mW) and 1.0x10⁴ W/cm² (10 mW) at 785 nm for the three spectra.