Abstract: Non-invasive [blood] glucose testing devices and testing methods without using a blood sample are disclosed and can be used for optically interrogating substances overlaid by turbid media based on wavefront manipulation by means of binary phase masking. Through altering the degree of mode conformity between the fields reaching the collection optics and the field distributions of the propagation modes of optical waveguides the disclosed method can be used to suppress the collection of short-range light originated near the collection optics while permitting unimpeded collection of light originated from sites substantially behind turbid media.