An infrared photodetector comprising: a thin contact layer substantially transparent to infrared light; an absorption layer positioned such that light admitted through the substantially transparent thin contact area passes through the absorption layer; the absorption layer being configured to utilize resonance to increase absorption efficiency; at least one reflective side wall adjacent to the absorption layer being substantially non-parallel to the incident light operating to reflect light into the absorption layer for absorption of infrared radiation; and a top contact layer positioned adjacent to the active layer. A method of designing a photodetector comprising selecting a type of material based upon the wavelength range to be detected; determining a configuration geometry; calculating the electromagnetic field distributions using a computer simulated design of the configuration geometry, and determining a quantum efficiency spectrum at the desired wavelength or wavelength range; whereby the effectiveness of the photodetector is simulated prior to fabrication.