A composite waveguide includes a central core configured to transmit a plurality of modes and at least one side core helically wound about the central core and configured to be selectively coupled to at least a portion of the plurality of modes in the central core. In example embodiments, the supply unit may include a plurality of compartments and each compartment may have a moving device configured to move contents of the compartment from a first end of the compartment to a second end of the compartment. These analogs are also useful in treating pulmonary or respiratory tract inflammation in humans. The thicknesses of the device is optimally in the range of about 10 to about 200 microns. When the illuminating beam 4 is incident on the sample 6, reflected electrons 8 are generated from the sample 6.