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; FIG. 8 is a bottom plan view thereof; and, FIG. 9 is an enlarged view of portion 9 of FIG. 2 thereof. The dash-dash broken lines shown in the drawings illustrate portions of the aroma diffuser that form no part of the claimed design. The dot-dash broken lines shown in the drawings depict the locations of enlarged views and the borders of enlarged views and form no part of the claimed design.