Patent ID: 8274027

Claim:
A laser energy detector, comprising: a photodetector formed on a semiconductor substrate, the semiconductor substrate having a front side and an opposing back side, the photodetector including an active area effective to detect laser energy within a first wavelength band, wherein the active area of the photodetector is substantially transparent for a second wavelength band within an infrared portion of the electromagnetic spectrum; and a back-side coating disposed on the back side of the semiconductor substrate at least over the active area, wherein the back-side coating is reflective for the first wavelength band and antireflective for the second wavelength band, the back-side coating including a plurality of alternating layers of a low refractive index material and a high refractive index material, the low refractive index material being one of CeF3 and YbF3 and the high refractive index material being one of ZnS and ZnSe.