Methods, apparatuses, and systems associated with a sample testing device are provided. For example, an example sample testing device may include a substrate layer defining a bottom surface of the sample testing device, as well as a waveguide disposed on the substrate layer and includes at least one reference channel and at least one sample channel.

Methods, apparatuses, and systems associated with a sample testing device are provided. For example, an example sample testing device may include a substrate layer defining a bottom surface of the sample testing device, as well as a waveguide disposed on the substrate layer and includes at least one reference channel and at least one sample channel.