Aroma diffuser

FIG. 1 is a front, right and top perspective view of an aroma diffuser showing my new design;

FIG. 2 is a rear, left and bottom perspective view thereof;

FIG. 3 is a front view thereof;

FIG. 4 is a rear view thereof;

FIG. 5 is a left side view thereof;

FIG. 6 is a right side view thereof;

FIG. 7 is a top plan view thereof; and,

FIG. 8 is a bottom plan view thereof.

The broken lines in the figures illustrate portions of the aroma diffuser that form no part of the claimed design.