CaltechAUTHORS: Book Chapter
https://feeds.library.caltech.edu/people/Mirhosseini-M/book_section.rss
A Caltech Library Repository Feedhttp://www.rssboard.org/rss-specificationpython-feedgenenThu, 19 Sep 2024 07:14:26 -0700Influence of Atmospheric Turbulence on the Performance of a High Dimensional Quantum Key Distribution System using Spatial Mode Encoding
https://resolver.caltech.edu/CaltechAUTHORS:20190717-091847143
Year: 2012
DOI: 10.1364/qim.2012.qw2a.3
The effects of atmospheric turbulence on a the channel capacity of a free-space quantum key distribution system with information encoded on the transverse modes of the photon are studied theoretically and experimentally.https://resolver.caltech.edu/CaltechAUTHORS:20190717-091847143Influence of thick atmospheric turbulence on the propagation of quantum states of light using spatial mode encoding
https://resolver.caltech.edu/CaltechAUTHORS:20190717-084844516
Year: 2012
DOI: 10.1364/cleo_at.2012.jtu2k.4
The effects of thick turbulence on transverse modes of light carrying orbital angular momentum are studied theoretically and experimentally. These results have potentially important implications for free-space quantum communications systems.https://resolver.caltech.edu/CaltechAUTHORS:20190717-084844516New results in quantum nonlinear optics
https://resolver.caltech.edu/CaltechAUTHORS:20190716-094956207
Year: 2012
DOI: 10.1109/ipcon.2012.6358696
The methods of nonlinear optics lead to important capabilities within the field of quantum information science. Applications such as high-capacity quantum key distribution and enhanced measurement sensitivity are described.https://resolver.caltech.edu/CaltechAUTHORS:20190716-094956207Direct Measurement of the Quantum Wavefunction using Weak Measurements in Orbital Angular Momentum
https://resolver.caltech.edu/CaltechAUTHORS:20190716-092901924
Year: 2012
DOI: 10.1364/fio.2012.fth4b.2
We propose a method that directly measures the photon wavefunction in the orbital angular momentum (OAM) basis by carrying out weak measurements in OAM and strong measurements in the conjugate basis of angular position.https://resolver.caltech.edu/CaltechAUTHORS:20190716-092901924Photon efficient wavefront sensing using an SLM for polarization-based weak measurements
https://resolver.caltech.edu/CaltechAUTHORS:20190716-094406367
Year: 2012
DOI: 10.1364/fio.2012.fw4a.3
A novel scheme is proposed for two dimensional direct measurement of wave functions using an SLM. This photon efficient method can be potentially useful for wavefront sensing of turbulence in adaptive optics systems used in free-space communication systems.https://resolver.caltech.edu/CaltechAUTHORS:20190716-094406367Amplification of Optical Pulse Delays using Weak Measurements
https://resolver.caltech.edu/CaltechAUTHORS:20190708-151341375
Year: 2013
DOI: 10.1364/cqo.2013.m6.02
A novel scheme for super-sensitive measurement of optical pulse delays is proposed based on the concept of weak-value amplification. We discuss an experimental implementation of this technique utilizing a Mach-Zehnder interferometer.https://resolver.caltech.edu/CaltechAUTHORS:20190708-151341375Sensitive estimation of angular displacements using weak measurements
https://resolver.caltech.edu/CaltechAUTHORS:20190708-151341314
Year: 2013
DOI: 10.1364/cqo.2013.m6.45
We demonstrate an experimental method that allows for sensitive measurements of angular position of light using weak value amplification. This offers an alternative to previously established methods that use nonclassical light for angular displacement estimation.https://resolver.caltech.edu/CaltechAUTHORS:20190708-151341314Nonlinear Optics: The Enabling Technology for Quantum Information Science
https://resolver.caltech.edu/CaltechAUTHORS:20190708-151341456
Year: 2013
DOI: 10.1364/nlo.2013.nw1a.1
Nonlinear optical processes such as parametric down conversion and squeezed light generation are key elements of most quantum protocols, leading to crucial applications such as quantum imaging, sub-shot-noise metrology, and secure communication.https://resolver.caltech.edu/CaltechAUTHORS:20190708-151341456Near-perfect sorting of orbital angular momentum: A step towards high-dimensional quantum communications
https://resolver.caltech.edu/CaltechAUTHORS:20190708-151341620
Year: 2013
DOI: 10.1364/fio.2013.fw4d.5
A novel technique is introduced for separation of orbital-angular-momentum (OAM) states of light. Using this method, we demonstrate the realization of a free-space communication link with a channel capacity of more than 4 bits per photon.https://resolver.caltech.edu/CaltechAUTHORS:20190708-151341620Visualizing Quantum State Rotations through Weak Measurements of Orbital Angular Momentum
https://resolver.caltech.edu/CaltechAUTHORS:20190708-151341699
Year: 2013
DOI: 10.1364/fio.2013.ftu1c.6
Using the technique of direct measurement, we observe the action of the angular momentum operator as the generator of rotations. Our method employs weak measurements of orbital angular momentum and strong measurements of angular position.https://resolver.caltech.edu/CaltechAUTHORS:20190708-151341699Recent Progress in Quantum Imaging and Ghost Imaging
https://resolver.caltech.edu/CaltechAUTHORS:20190628-110703214
Year: 2013
DOI: 10.1364/fio.2013.fw5d.1
We summarize recent work that demonstrates the utility of quantum effects for important technological applications in image science. We emphasize that what was considered to be "quantum weirdness" only a few years ago is today useful technology.https://resolver.caltech.edu/CaltechAUTHORS:20190628-110703214Towards Quantum Communication with more than 4 bits/photon: Near-Perfect Sorting of the Orbital Angular Momentum Modes of Light
https://resolver.caltech.edu/CaltechAUTHORS:20190628-110703857
Year: 2014
DOI: 10.1364/qim.2014.qw3a.6
We demonstrate a method that uses a series of optical transformations to sort the orbital angular momentum and the mutually-unbiased angular position modes of light with a separation efficiency of more than 92%.https://resolver.caltech.edu/CaltechAUTHORS:20190628-110703857Compressive Direct Measurement of the Transverse Photonic Wavefunction
https://resolver.caltech.edu/CaltechAUTHORS:20190628-110704136
Year: 2014
DOI: 10.1364/fio.2014.fm4e.5
We generalize the method of direct measurement and combine it with compressive sensing. Using our method, we measure a 19200-dimensional state using only 20% of the total required measurements.https://resolver.caltech.edu/CaltechAUTHORS:20190628-110704136Measurement of the Second Order Coherence of Pseudo-Thermal Light in the Azimuthal Degree of Freedom
https://resolver.caltech.edu/CaltechAUTHORS:20190628-110704048
Year: 2014
DOI: 10.1364/fio.2014.ftu1g.6
Using an angular version of the Hanbury Brown Twiss interferometer, we show for the first time second-order interference in the azimuthal degree of freedom, which exhibits higher resolution fringes than if coherent light were used.https://resolver.caltech.edu/CaltechAUTHORS:20190628-110704048High-dimensional Quantum Key Distribution with Photonic Orbital Angular Momentum
https://resolver.caltech.edu/CaltechAUTHORS:20190628-110704267
Year: 2014
DOI: 10.1364/fio.2014.fm4e.4
We experimentally demonstrate a quantum cryptography system based on photonic orbital angular momentum. The system achieves a channel capacity of 2.1 bits per sifted photon through the use of a 7-dimensional alphabet for encoding information.https://resolver.caltech.edu/CaltechAUTHORS:20190628-110704267Direct measurement of the quantum density matrix in the basis of azimuthal angle
https://resolver.caltech.edu/CaltechAUTHORS:20190628-110704960
Year: 2015
DOI: 10.1364/cleo_qels.2015.ftu4a.2
We theoretically propose and experimentally demonstrate a method for directly measuring the density matrix of an unknown quantum system in the basis of azimuthal angle. We apply our method for characterizing 7-dimensional pure and mixed superpositions of orbital-angular-momentum modes.https://resolver.caltech.edu/CaltechAUTHORS:20190628-110704960Q-plates for Switchable Excitation of Fiber OAM Modes
https://resolver.caltech.edu/CaltechAUTHORS:20190628-110704866
Year: 2015
DOI: 10.1364/cleo_si.2015.sw4m.3
We demonstrate that a |q|=1/2 plate plus polarization optics can tunably excite all linear combinations of |l|=1 fiber OAM modes with up to ~30 dB purity, enabling switch fabrics in fiber-OAM networks and disentangling of degenerate mode mixing effects in long fibers.https://resolver.caltech.edu/CaltechAUTHORS:20190628-110704866Scan-free direct measurement of an one-million-dimensional photonic state
https://resolver.caltech.edu/CaltechAUTHORS:20190628-110705149
Year: 2015
DOI: 10.1364/fio.2015.fw4d.6
We describe a technique that directly measures a pure quantum state of arbitrary dimensions with a single setting of the measurement apparatus. We demonstrate our method by measuring a million-dimensional photonic spatial state.https://resolver.caltech.edu/CaltechAUTHORS:20190628-110705149Recent progress in weak value amplification and direct measurement
https://resolver.caltech.edu/CaltechAUTHORS:20190716-080008044
Year: 2016
DOI: 10.3254/978-1-61499-647-7-77
The ability to manipulate light has allowed scientists to verify fundamental theories of physics and to develop a new generation of technologies that use photons as a primary resource. Recent developments in quantum measurement theory have offered new alternatives to approach some of the most remarkable problems in quantum physics. Consequently, the principles of quantum mechanics have been exploited in the development of quantum technologies such as optical metrology, quantum communication, and quantum information. In recent years, weak measurements and two of its most remarkable variants: weak value amplification and direct measurement, have been developed and are considered important resources for quantum applications. In this paper, we discuss weak measurements and some significant applications of weak values. We elaborate on how distinct forms of weak values are used to observe and amplify small effects or to directly measure the quantum wave function of photons, a crucial task for schemes for quantum communication and quantum information. We also review some of the most recent methods for weak value amplification and direct measurement that our group has developed.https://resolver.caltech.edu/CaltechAUTHORS:20190716-080008044Direct measurement of an one-million-dimensional photonic state
https://resolver.caltech.edu/CaltechAUTHORS:20190717-080451530
Year: 2016
DOI: 10.1109/piers.2016.7734289
The state vector of a pure quantum system is a set of complex probability amplitudes used for describing the system in each state of a given Hilbert space. Characterizing the state of a quantum system is crucial for fundamental studies in quantum mechanics as well as for manipulating and utilizing quantum systems for practical applications. Here we describe a scan-free direct measurement approach [1] that is capable of simultaneously measuring the entire state vector of a pure quantum system, consequently eliminating the need for scanning through each basis state. Our method involves a proper arrangement of weak [2, 3] and strong measurements. Specifically, to measure the state vector of a quantum system in one
Hilbert space A, one first applies a weak measurement to the quantum system in one fixed state |b_0〉. of its complementary basis B, and then performs the strong measurement directly in A. As an example, we have designed a procedure of measuring the transverse spatial state of a photon, which is a convenient high-dimensional quantum system for study, and which has a well- understood classical analogue as the transverse complex field profile of an optical beam. In order to measure the complex probability amplitude of a photon at a position state x, one first performs a weak projection measurement of the zero momentum state p_0 = 0, followed by a strong measurement of the position state. Through such a procedure, the measured weak values are inversely proportional to the state vector of the quantum system. To demonstrate our method, we characterize photons carrying different spatial modes, such as uniform amplitude and Zernike phase profiles, circular mode carrying orbital angular momentum (OAM) [4, 5], etc. Since one can have independent control of the complex probability amplitude of the photons at each pixel of the transverse space, the dimensionality of our measured state is approximately 1.2 million, which is determined by the spatial extent of the photons (approximately 7mm in diameter) and the discrete nature of our detector array (with pixel size of 5.4 µm^2). The fidelity of the photon state in the spatial Hilbert space is calculated to be approximately 0.93. Such a high fidelity of our result demonstrates that our direct measurement technique is indeed capable of measuring the complex-value quantum state vector with very high accuracy. Our scan-free direct measurement approach opens up the possibility to characterize high dimensional quantum systems in real time for which a state-by-state scanning process would become impractically time-consuming or even infeasible. Moreover, our specific demonstration of measuring photons' transverse spatial state is also a promising new technology for classical wavefront sensing applications in fields as diverse as observational astronomy, free-space optical communication, and biomedical imaging.https://resolver.caltech.edu/CaltechAUTHORS:20190717-080451530Non-local angular double-slit ghost diffraction with thermal light
https://resolver.caltech.edu/CaltechAUTHORS:20190708-151342257
Year: 2016
DOI: 10.1364/fio.2016.jth2a.14
We report an experimental observation of ghost diffraction with non-local angular double-slit by making use of thermal light and orbital angular momentum (OAM) correlation measurement. A correlated angular interference pattern of the distributed angular double-slit is measured.https://resolver.caltech.edu/CaltechAUTHORS:20190708-151342257Quantum Information with Structured Light
https://resolver.caltech.edu/CaltechAUTHORS:20190708-151342166
Year: 2016
DOI: 10.1364/ls.2016.ltu1e.3
We investigate structured photons as carriers of quantum information. We describe our implementation of quantum cryptography with orbital angular momentum, and present our results on efficient implementation of quantum state tomography for structured light fields.https://resolver.caltech.edu/CaltechAUTHORS:20190708-151342166Measuring Exotic Looped Trajectories of Light
https://resolver.caltech.edu/CaltechAUTHORS:20190708-151342343
Year: 2016
DOI: 10.1364/fio.2016.fw2e.5
The probability of a photon to follow looped trajectories in a three-slit interferometer is extremely small and difficult to measure. We unveil the underlying physics and implications behind these trajectories and present their first observation.https://resolver.caltech.edu/CaltechAUTHORS:20190708-151342343Sorting Laguerre-Gaussian modes by radial quantum number
https://resolver.caltech.edu/CaltechAUTHORS:20190708-151342758
Year: 2018
DOI: 10.1364/cleo_at.2018.jth2a.4
An efficient sorter based on the fractional Fourier transform is realized to detect the radial quantum number of the Laguerre-Gaussian modes. The reported scheme can, in principle, have unit efficiency and no cross-talk.https://resolver.caltech.edu/CaltechAUTHORS:20190708-151342758Performance analysis of d-dimensional quantum cryptography with mode-dependent diffraction
https://resolver.caltech.edu/CaltechAUTHORS:20190716-090724755
Year: 2018
DOI: 10.1364/cleo_at.2018.jth2a.19
We analyze the degraded performance of QKD that results from mode-dependent diffraction in spatial-mode-encoded QKD systems. A pre-compensation method is proposed to solve this problem without sacrificing the security.https://resolver.caltech.edu/CaltechAUTHORS:20190716-090724755Direct Measurement of the Photon's Spatial Wave Function
https://resolver.caltech.edu/CaltechAUTHORS:20190716-081016277
Year: 2019
DOI: 10.1007/978-3-319-98402-5_2
We overview recent progress in the tomography of structured light fields, with an emphasis on the method of direct measurement. Direct measurement provides a scalable and easy- to-implement approach for characterizing the transverse structure of single photons. This protocol is particularly attractive in light of the emerging role of high-dimensional optical states as a resource for encoding quantum information. We present a summary of various implementations of this technique that aim to characterize the spatial degree of freedom of the optical field.https://resolver.caltech.edu/CaltechAUTHORS:20190716-081016277