Hwang Lee, Ph.D.


Hwang Lee, PhD
associate Professor of Physics
Ph.D., 1998  Texas A&M University
Louisiana State University
Department of Physics & Astronomy
451 Nicholson Hall, Tower Dr.
Baton Rouge, LA 708034001
(225) 5782365Office
Quantum Science and Technologies Group
Research Interests
Quantum Optics/Quantum Information Processing
The primary focus is generation of nonclassical states of radiation fields and their applications in precision measurements, quantum computing, and communication. Current interests include design of efficient singlephoton sources and detectors, multiphoton entanglement, enhancement of nonlinear optical processes using atomic coherence, and singlephoton 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 socalled standard quantum limit (or the shotnoise 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 shotnoise limit of 1/$\sqrt{N}$ 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 photonsless optical power and less radiationpressure 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 outputmeasurement strategies for such quantum enhanced optical interferometers. We apply the results of theoretical and numerical analyses to design interferometer devices with such as twomode squeezed state inputs and photodetectors that measure only the eveness/oddness of the number of photons without counting.
Current and Selected Publications
 Seshadreesan, KP; Kim S; Dowling JP; Lee, H, "Phase estimation at the quantum CramerRao bound via parity detection," Physical Review A 87, 043833 (2013).
 Gard, BT; Cross, RM; Anisimov, PM; Lee, H; Dowling, JP, "Quantum random walks with multiphoton interference and highorder correlation functions," Journal of Optical Society of America B 30, 1538 (2013).
 Roy Bardhan B; Anisimov, PM; Gupta, MK; Brown KL, Jones, NC; Lee, H; Dowling, JP, "Dynamical decoupling in optical fibers: Preserving polarization qubits from birefringent dephasing," Physical Review A 85, 022340 (2012).
 Seshadreesan, KP; Anisimov, PM; Lee, H; Dowling, JP, "Parity detection achieves the Heisenberg limit in interferometry with coherent mixed with squeezed vacuum light," New Journal of Physics 13, 083026 (2011).
 Chiruvelli, A; Lee, H, "Parity Measurement in Quantum Optical Metrology," Journal of Modern Optics 58, 945953 (2011).
 Plick, WN, Anisimov, PM; Dowling, JP; Lee, H; Agarwal, GS, "Parity detection in quantum optical metrology without numberresolving detectors," New Journal of Physics 12, 113025 (2010).
 Anisimov, PM; Raterman, GM; Chiruvelli, A; Plick, WN; Huver, SD; Lee, H; Dowling, JP, "Quantum Metrology with TwoMode Squeezed Vacuum: Parity Detection Beats the Heisenberg Limit," Physical Review Letters 104, 103602 (2010).
 Gao, Y; Wildfeuer, CF; Anisimov, PM; Luine J; Lee, H; Dowling, JP, "SuperResolution at the ShotNoise Limit with Coherent States and PhotonNumberResolving Detectors," Journal of Optical Society of America B 27, A170 (2010).
