Abstract: This invention relates to measurements of material properties by determination of the response of a sample to incident radiation, and more specifically to the measurement of analytes such as glucose or alcohol in human tissue. Some example embodiments of the present invention provide an optical sampling apparatus including an optical subsystem, having a receiver for receiving light expressed from tissue; and an alignment subsystem, adapted to urge a portion of a hand placed in operative relationship with the alignment subsystem into a defined configuration relative to the receiver. In some such example embodiments, the alignment subsystem includes a substrate having a plurality of projections therefrom disposed in a pattern such that the projections urge a portion of a hand placed on the substrate to a defined configuration relative to the receiver.