A spooky light-emitting diode

C. L. Salter, R. M. Stevenson, Ian A. Farrer +3 more

Jungsang Kim, Seema Somani, Y. Yamamoto

Patrick Janassek, Sébastien Blumenstein, Wolfgang Elsäßer

Ghost modalities are by no means ``spooky actions'', but are metrology schemes exploiting intensity correlations of light, based on the fundamentals of quantum optics. The authors demonstrate ghost spectroscopy based on classical photon correlations in the wavelength domain of broad-band light emitted by an ultraminiaturized superluminescent semiconductor diode. Comprehensive proof of principle is provided by a real-world experiment on chloroform at 1214 nm. This demonstrated analogy between ghost imaging and ghost spectroscopy is expected to further fertilize the field, to promote a deeper understanding, and to lead even to other protocols in ghost metrology.

K. Tanaka, Yutaka Kadoya, Hiroyuki Yuji +2 more

Summary form only given. Generally, light-emitting diodes (LEDs) are considered to be low-performance devices in comparison with laser diodes (LDs). However, for future applications such as the parallel inter- or intra-integrated-circuit chip optical-connections, where very low power-consumption is required for the light emitters, a LED can be a very attractive device because of the threshold-free input-output characteristics. So far, continuous efforts have been made to improve the performance of LEDs. In this paper, we focus on another very important aspect, i.e. the noise characteristics. In comparison with LDs, in general, LEDs exhibit excellent noise characteristics, particularly at low injection levels. We show that the intensity fluctuation of the output light from an LED can be squeezed below the full shot-noise (FSN) level in a wide frequency range up to 800 MHz at room temperature. Such a squeezing bandwidth, three orders of magnitude wider than that in the first report on shot-noise suppression in a LED and rather close to the widest bandwidth (1.1 GHz) obtained with LDs at 77 K has been believed to be impossible. In addition, use of a separate confinement hetero(SCH-) structure in the active region allowed us to use a moderate doping concentration (5 /spl times/ 10/sup 18/ cm/sup -3/), resulting in a sufficiently high internal quantum efficiency, /spl sim/30%.

竜二 増山, A. Higashi, K. Tanaka +2 more

We have investigated the squeezing of intensity-fluctuation below the full-shot-noise level in light-emitting diodes (LEDs) at low-photon flux levels. By using a tailor-made LED, the squeezing over a wide frequency range, near-dc to 1.5 GHz was achieved at an injection-current level as low as 100 μA. As a result, the number of photons, which can be expected in the sub-Poissonian light, was reduced to the order of 105 per pulse, nearly three orders of magnitude smaller than those obtained in commercial LEDs.