Figure 4. Raman spectra of the outer segments exciting at 514 nm

Raman spectra of the outer segments of porcine retinal section were acquired using 514 nm excitation. The labeled modes are discussed in the text. The outer nuclear layer and photoreceptor outer segment spectra closely resemble those recorded at 785 and 633 nm (Figure 1, Figure 3), suggesting an absence of resonance enhancement in the Raman scattering originating from these layers. A significant difference is evident in the PIS layer, with the cytochrome c features in the 1500-1630 cm^-1 and 1330-1400 cm^-1 ranges showing larger signal enhancement than at 633 nm.