Program

SESSION 7: Quantum optics

Chair: (Alberto Marino (University of Oklahoma))
10:15am-11:00amBrian Smith, University of Oregon
Control and measurement of single-photon pulses
Abstract. The ability to manipulate the spectral-temporal waveform of optical pulses in the classical domain has enabled a wide range of applications from ultrafast spectroscopy to high-speed communications. Extending these concepts to quantum light has the potential to enable breakthroughs in optical quantum science and technology. However, filtering and amplifying often employed in classical pulse shaping techniques are incompatible with non-classical light. Controlling and efficiently measuring the pulsed mode structure of quantum light requires efficient means to achieve deterministic, unitary manipulation that preserves fragile quantum coherences. Here an approach to deterministically modify the pulse-mode structure of quantum states of light within an integrated optical platform is presented. The method is based upon application of both spectral and temporal phase modulation to the wave packet. These techniques lay the ground for future quantum wavelength- and time-division multiplexing applications and facilitate interfacing of different physical platforms where quantum information can be stored and manipulated.
11:00am-11:30amMatthew DiMario, University of New Mexico CQuIC
A robust, single-shot measurement for binary phase-shift keyed coherent state discrimination
Abstract. The discrimination of binary phase-shift keyed (BPSK) coherent states is an integral part of many classical and quantum communication schemes. While complex measurement strategies employing feedback can far surpass the Quantum Noise Limit (QNL) set by a Homodyne measurement, there is also a need for non-adaptive strategies that can be scaled to high bandwidths and incorporated into current and future communication methods. Moreover, all measurement strategies are subject to non-ideal conditions and must be able to overcome realistic noise and imperfections in real-world communication channels while keeping their sensitivity performance. We investigate and experimentally demonstrate a robust, high-sensitivity discrimination strategy for BPSK coherent states that is based on a single, optimized displacement operation in phase space followed by photon counting. Robustness of the discrimination strategy comes from the information gained through a photon number resolving (PNR(m)) measurement, corresponding to projections onto Fock states up to a threshold of “m” photons, which characterizes the finite number resolution of realistic detectors. Optimal single shot measurements are compatible with high-bandwidth communication while being able to achieve sensitivities below the QNL under realistic conditions. Our experimental demonstration with a realistic detector and finite photon number resolution, allows the measurement to continually outperform the QNL, adjusted for our detection
11:30am-12:00pmTimothy Woodworth, University of Oklahoma
Reaching the quantum Cramér-Rao bound of transmission measurements
Abstract. The quantum Cramér-Rao bound (QCRB) is commonly used to quantify the lower bound for the uncertainty in the estimation of a given parameter. Here, we calculate the QCRB for transmission measurements of an optical system probed by a beam of light. Estimating the transmission of an optical element is important as it is required for the calibration of optimal states for interferometers, characterization of high efficiency photodetectors, or as part of other measurements, such as those in plasmonic sensors or in ellipsometry. We use a beam splitter model for the losses introduced by the optical system to calculate the QCRB for different input states. We compare the bound for a coherent state, a two-mode squeezed-state (TMSS), and a Fock state. We prove that the Fock state gives the lowest possible uncertainty in estimating the transmission for any state and demonstrate that the TMSS approaches this ultimate bound for large levels of squeezing. Finally, we show that a simple measurement strategy for the TMSS, namely an intensity difference measurement, is able to saturate the QCRB. We then perform experiments to show this.

SQuInT Chief Organizer
Akimasa Miyake, Assistant Professor
amiyake@unm.edu

SQuInT Co-Organizer
Mark M. Wilde, Assistant Professor LSU
mwilde@phys.lsu.edu

SQuInT Administrator
Gloria Cordova
gjcordo1@unm.edu
505 277-1850

SQuInT Founder
Ivan Deutsch, Regents' Professor
ideutsch@unm.edu

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