Multistep staircase avalanche photodiodes with extremely low noise & deterministic amplification (lidar)

Amplifying light for lidar


Engineers at University of Texas at Austin and University of Virginia developed a light detector that can amplify weak light signals and reduce noise to improve the accuracy of lidar.

Find technical paper here.


“In 1982, Capasso and co-workers proposed the solid-state analogue of the photomultiplier tube, termed the staircase avalanche photodiode. Through a combination of compositional grading and small applied bias, the conduction band profile is arranged into a series of steps that function similar to the dynodes of a photomultiplier tube, with twofold gain arising at each step via impact ionization. A single-step staircase was previously reported but did not demonstrate gain scaling through cascading multiple steps or report noise properties. Here we demonstrate gain scaling of up to three steps; measurements show the expected 2N scaling with the number of staircase steps, N. Furthermore, measured noise increased more slowly with gain than for photomultiplier tubes, probably due to the lower stochasticity of impact ionization across well-designed heterojunctions as compared with the secondary electron emission from metals. Excellent agreement was found between the experiments and Monte Carlo simulations for both gain and noise.”

Stephen D. March, Andrew H. Jones, Joe C Campbell & Seth R. Bank


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