An apparatus for extracting a vaporizable substance, from a material containing such substance, comprises an irradiation chamber for irradiating the material with electromagnetic radiation to vaporize the substance. The substance may comprise water and the material is dehydrated. The electromagnetic radiation comprises microwaves. The irradiation is conducted in the near-field range of the electromagnetic radiation. In one aspect, the electromagnetic radiation within the waveguide evanescently couples with the material.
