The present invention provides apparatuses including a point light source, a diffraction grating oriented in a light path generated from the point light source wherein the diffraction grating diffracts and concentrates light from the point light source into one or more rings of light, a detector positioned to detect one or more of the rings of light or light transmitted from a sample exposed to said rings of light, and a computer operably connected to the detector to analyze the intensity of one or more of the rings of light or said light transmitted from said sample. Variations including samples and additional components and methods of making the apparatuses of the present invention are also disclosed.