Quantum Nano-Optics of Semiconductors

Nano-Spectroscopy Laboratory

Dr. Hyatt Gibbs and Dr. Galina Khitrova. Instrumentation includes a nanoscope for high resolution spectroscopy as well as continuous argon and Ti:Sa lasers for excitation.  The custom-built nanoscope allows for high precision spectroscopy with high spatial resolution and holds samples on a cold finger capable of operating below 4K. The cold finger system is attached to a turbomolecular pump allowing the sample to be excited in a vacuum of 10-9 torr. The cold finger sits on top of an X-Y-Z micropositioning stage capable of submicron movement. Samples may be excited by either laser or broadband LED. The nanoscope is built so that the excitation may be performed using any one of several sources by simply sliding a shutter or flipping a mirror and is capable of performing measurements of either photoluminescence, reflectivity, or transmission.  Detection is performed by first passing the light through a spectrometer with a holographic grating and then recording the spectra with a cryogenically cooled CCD.  The CCD data are then automatically sent to a standard Windows PC. The spatial resolution of the nanoscope at a wavelength of 750 nm is 800 nm, while the spectrographic resolution is 0.02 nm.

Low Temperature and High Magnetic Field Laboratory

Dr. Hyatt Gibbs and Dr. Galina Khitrova. Research focuses on transmission, reflection and differential reflection spectroscopy.  Instrumentation includes multiple computer-controlled spectrometers, an APD cryogenic cooling system, 12 T superconducting magnet, and 300 mK 3He refrigerator.

fs-Spectroscopy Laboratory

Dr. Hyatt Gibbs and Dr. Galina Khitrova. Exciton formation following nonresonant picosecond excitation is studied by time-dependent photoluminescence and differential absorption. Instrumentation includes a femtosecond Ti:Sa laser, streak camera, and cryogenically cooled CCD.

MBE System Laboratory

Dr. Hyatt Gibbs and Dr. Galina Khitrova. A three-chamber Riber 32P MBE (molecular beam epitaxy) system is used for the growth of InGaAs/GaAs, GaAs/AlGaAs, GaAlInAs structures.  The ion-pumped load chamber includes a unit for the prebaking of moly blocks and samples, including wafers up to three inches.  The chamber for growing samples contains Ga, As, In, and Al effusion cells, RHEED analysis and a quadrupole mass analyzer. The temperatures of the cells are maintained by feedback control and shutter actuations are computer controlled.

Quantum Nano-Optics of Semiconductors Facilities

Dr. Hyatt Gibbs and Dr. Galina Khitrova. Faculty members and students perform research in semiconductor physics and nonlinear optics. Current projects include linear and nonlinear exciton physics in quantum wells and quantum dots.  Other efforts involve the study of radiative coupling effects and include normal mode coupling in planar semiconductor microcavities, strong coupling in semiconductor nanocavities with the goal of reaching the quantum limit, and radiative coupling of periodically positioned quantum wells and 3D optical lattices.  MBE growth is yet another priority area of study.