I have observed unusual shapes of Raman bands of hydrogen sulfide composed of a total of three components during measurements of CH4-H2S fluid inclusions in quartz using a Nd-YAG 532 nm laser excitation and 2400 gr/mm grating. In contrast, only simple H2S band occurs using the same analytical conditions with another grating, e.g. 1800 gr/mm. The phantom bands appear also without any sample in the laser path, and the position of the major phantom band changes linearly with the spectrometer position (see upper figure) according to the equation y=2.8x-4473 (x – phantom band position, y – spectrometer position). The phantom bands lie outside the spectral window for spectrometer positions >2970 cm-1 and their intensity tends to diminish with the shift of spectrometer positions towards lower wavenumbers. However, at longer acquisition times, the phantom band (in fact doublet), though invisible in the RTD mode with short acquisition times, typically 1 sec., is still strong enough to interfere with that of H2S (see bottom figure). Could someone provide a reasonable physical explanation for this phenomenon?