David Snoke

Department of Physics and Astronomy, University of Pittsburgh
Ph.D., Physics, University of Illinois at Urbana-Champaign, 1990
Summary:

Our experimental group uses a wide array of optical methods to study fundamental questions of quantum mechanics in semiconductor systems. Our optical methods include ultrafast spectroscopy on femtosecond and picosecond time scales, single photon counting and correlation, real-space and momentum space (Fourier) imaging with CCD cameras, and nonlinear optics such as two-photon absorption and the optical Stark effect. We can also apply variable stress to samples to create potential gradients to move particles inside solids, vary temperature down to cryogenic temperatures, and measure transport with electronics. 

One of the main efforts in our lab at present is the study of polariton condensates in microcavities. The polaritons are essentially photons dressed with an effective mass and strong interactions due to the special design of the solid-state microcavity structures we use. These interacting photons can undergo Bose-Einstein condensation, which is a state of matter with spontaneous coherence. We can see superfluid flow of the polariton condensate over millimeter distances; we can also trap the condensate in various potentials; and we can see interference due to the coherence of the condensate. 

This work connects to several fundamental questions. One topic is how coherence can occur spontaneously ("enphasing") in systems like lasers and condensates and how coherence is lost ("dephasing") in standard quantum systems.  This, in turn, relates to the deep question of why there is irreversibility in nature, that is, the arrow of time. Another topic is how phase transitions can occur in nonequilibrium systems. We have developed sophisticated numerical methods to compare  the solution of a quantum Boltzmann equation (which gives the temporal evolution of a system in nonequilibrium) to our data on the momentum and energy distributions of gases of various particles.

A new effort in our group is looking at using a polariton condensate to modulate the two-photon absorption in our samples. This may be used for special nonlinear effects in quantum computing schemes. We have also looked at spin flip and other dynamic processes of electrons and holes in quantum dots, dipolar excitons in quantum wells, and various methods of modulating light in semiconductor lasers and microcavities for applied optical communications goals. 

Students
Namesort descending Position Email
Beaumariage, Jonathan Graduate Student jcb130@pitt.edu
Grusky, Adam Undergraduate Student AdamGrusky@msn.com
Mukherjee, Shouvik Graduate Student shm110@pitt.edu
Myers, David Graduate Student dmm154@pitt.edu
Ozden, Burcu Postdoctoral Fellow burcu2@pitt.edu
Sun, Zheng Postdoctoral Fellow sunzhengnanophy@gmail.com

Jonathan Beaumariage


Graduate Student

jcb130@pitt.edu
3941 O'Hara Street, Pittsburgh PA, 15260

Affiliation:

Physics
University of Pittsburgh

Adam Grusky


Undergraduate Student

AdamGrusky@msn.com
G-10 Allen Hall, Pittsburgh PA, 15213

Affiliation:

Physics
University of Pittsburgh

Shouvik Mukherjee


Graduate Student

shm110@pitt.edu
3941 O'Hara Street, Pittsburgh PA, 15260
(412) 624-9096

Affiliation:

Physics
University of Pittsburgh

David Myers


Graduate Student

dmm154@pitt.edu
3941 O'Hara Street, Pittsburgh PA, 15260

Affiliation:

Physics
University of Pittsburgh

Burcu Ozden


Postdoctoral Fellow

burcu2@pitt.edu
3941 O'Hara Street, Pittsburgh PA, 15260

Affiliation:

Physics
University of Pittsburgh

Zheng Sun


Postdoctoral Fellow

sunzhengnanophy@gmail.com
G-10 Allen Hall, Pittsburgh PA, 15213

Affiliation:

Physics
University of Pittsburgh
Most Cited Publications
  1. "Bose-Einstein condensation of microcavity polaritons in a trap," R Balili, V Hartwell, D Snoke, L Pfeiffer, K West, Science 316, 1007 (2007)
  2. "Bose-einstein condensation," Allan Griffin, David Snoke, and Sandro Stringari, Cambridge University Press (1996)
  3. "Bose-Einstein condensation of excitons and biexcitons: and coherent nonlinear optics with excitons," SA Moskalenko, D SnokeCambridge University Press (2000)
  4. "Spontaneous Bose coherence of excitons and polaritons," D SnokeScience 298, 1368 (2002)
  5. "Long-range transport in excitonic dark states in coupled quantum wells," D. Snoke, S. Denev, Y. Liu, L. Pfeiffer & K. W, Nature, 418, 754 (2002)
Recent Publications
  1. "Measurement of polariton-polariton interaction strength in the Thomas-Fermi regime of polariton condensation," E. Estrecho, T. Gao, N. Bobrovska, D. Comber-Todd, M. D. Fraser, M. Steger, K. West, L. N. Pfeiffer, J. Levinsen, M. M. Parish, T. C. H. Liew, M. Matuszewski, D. W. Snoke, A. G. Truscott & E. A. Ostrovskaya, arXiv:1809.00757v1
  2. "Pushing Photons with Electrons: Observation of the Polariton Drag Effect," D. M. Myers, B. Ozden, J. Beaumariage, and D. W. Snoke, arXiv:1808.07866v2 (2018)
  3. "Single-shot condensation of exciton polaritons and the hole burning effect," E. Estrecho, T. Gao, N. Bobrovska, M.D. Fraser, M. Steger, L. Pfeiffer, K. West, T.C.H. Liew, M. Matuszewski, D.W. Snoke, A.G. Truscott10 & E.A. Ostrovskaya, Nature Communication 9, 05349 (2018)
  4. "Effect of quantum confinement on the blueshift of optically-trapped exciton polaritons below the condensation threshold," Maciej Pieczarka, Maryam Boozarjmehr, Eliezer Estrecho, Mark Steger, Kenneth West, Loren N. Pfeiffer, David W. Snoke, Andrew G. Truscott and Elena A. Ostrovskaya, arXiv:1808.00749v2
  5. Polariton-Enhanced Exciton Transport D. M. Myers, S. Mukherjee, J. Beaumariage, D. W. Snoke, M. Steger, L. N. Pfeiffer and K. West, arXiv:1807.11905v2
  6. "Superlinear increase of photocurrent due to stimulated scattering into a polariton condensate," D. M. Myers, B. Ozden, M. Steger, E. Sedov, A. Kavokin, K. West, L. N. Pfeiffer, and D. W. SnokePhys. Rev. B (2018).
  7. "Direct measurement of polariton–polariton interaction strength," Yongbao Sun, Yoseob Yoon, Mark Steger, Gangqiang Liu, Loren N. Pfeiffer, Ken West, David W. Snoke, & Keith A. Nelson, Nature Physics 13, 870–875 (2017)

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