A filter device for reducing the amount of non-vaporous components in a vapour stream, including a carbon foam as filter material capable of being penetrated by the vapour stream and arranged in such a way that the only route for the vapour stream to pass the carbon foam is via penetration of the carbon foam. The device is in particular suitable for coating a substrate by physical vapour deposition of the vapour. The homogenous and single phase vapour stream produced by the filter device results in a smooth coated substrate wherein splashes are virtually absent.