Generation of Extremely Weak Sub-Poissonian Light Using High-Efficiency Light-Emitting Diodes

The squeezing of the intensity noise in the extremely weak light emanating from a light-emitting diode (LED) was investigated. By the use of a tailor-made high-efficiency LED, in which the active region is heavily doped (~3.5×1019 cm-3), we successfully observed sub-Poissonian light at an injection current and photocurrent as low as 1 µA and 160 nA, respectively, at room temperature. The experimental results also implied that the theoretical model describing the noise behavior needs to be refined, particularly in the case of extremely low injection levels where the nonradiative recombination process has a serious effect.