Midinfrared optical upconverter

We have developed a midinfrared optical upconverter by wafer bonding a $\mathrm{Ga}\mathrm{As}∕\mathrm{Al}\mathrm{Ga}\mathrm{As}$ light-emitting diode with an InSb $p^{+}n{n}^{+}$ photodetector. The device converts midinfrared radiation in the range of $3–5.45\mu \mathrm{m}$ to near-infrared light at $0.84\mu \mathrm{m}$ , which can be efficiently detected using a widely available Si charge coupled device. At $77\mathrm{K}$ , the measured external upconversion efficiency was $0.093\mathrm{W}∕\mathrm{W}$ . The optical up-conversion device, in combination with the Si CCD camera, leads to an alternative solution for making low-cost and large-area midinfrared imaging device. Effects of electrical gain and photon recycling inside this integrated device are discussed.