Ph.D., 1998 - Texas A&M University
Louisiana State University
Department of Physics & Astronomy
451 Nicholson Hall, Tower Dr.
Baton Rouge, LA 70803-4001
The primary focus is generation of non-classical states of radiation fields and their applications in precision measurements, quantum computing, and communication. Current interests include design of efficient single-photon sources and detectors, multi-photon entanglement, enhancement of nonlinear optical processes using atomic coherence, and single-photon quantum nondemolition measurements.
Optical interferometry provides one of the finest tools for precision measurement. Basically it is to determine the unknown phase difference, imprinted by the physical quantity of interest, between the two paths of light propagation. The maximum capability of the interferometer is limited by the inherent uncertainty imposed by quantum mechanics. If the input source of the interferometer is classical, such as the light from a laser, the phase sensitivity is limited by the so-called standard quantum limit (or the shot-noise limit, in a somewhat narrow sense). The newly emergent field of quantum metrology utilizes certain quantum effects, such as quantum coherence, quantum entanglement, and squeezing, to push the capability of the interferometer beyond the standard quantum limit. The improvement in the sensitivity from the shot-noise limit of 1/N scaling to the ultimate limit, the Heisenberg limit of 1/N (where N is the average of input number of photons, representing the intensity of light) means that the same sensitivity can be achieved with less number of photons-less optical power and less radiation-pressure noise. Such reduction of the light intensity at the same level of sensitivity and resolution will provide huge benefits for any interferometric precision measurement and remote sensing, and may provide crucial advances in biomedical sensing where light intensity is a critical restriction. We study quantum correlations input states of light, quantum state engineering to produce desired inputs, and output-measurement strategies for such quantum enhanced optical interferometers. We apply the results of theoretical and numerical analyses to design interferometer devices with such as two-mode squeezed state inputs and photodetectors that measure only the eveness/oddness of the number of photons without counting.