The present disclosure relates to devices and methods for detecting and removing vapor for an imaging acquisition device. A device for detecting and removing vapor may include a first light guide. The first light guide may include a first end to receive a light beam, and a second end to output the light beam at a predetermined angle with respect to a reference plane, so that when the light beam enters a target light transmission media from the first light guide, the light beam substantially perfectly reflects between a first surface and a second surface of the target light transmission media. The first surface and second surface may substantially parallel to the reference plane.