A5014102584- Photonic and Optical Devices
- Random lasers and scattering media
- Neural Networks and Reservoir Computing
- Photonic Crystals and Applications
- Quantum Information and Cryptography
- Semiconductor Lasers and Optical Devices
- Semiconductor Quantum Structures and Devices
- Terahertz technology and applications
- Quantum optics and atomic interactions
- Optical Network Technologies
- Advanced Optical Imaging Technologies
- Orbital Angular Momentum in Optics
- Advanced Optical Sensing Technologies
- Physical Unclonable Functions (PUFs) and Hardware Security
- Mechanical and Optical Resonators
- Optical Coatings and Gratings
- Nanofabrication and Lithography Techniques
- Diffusion and Search Dynamics
- Laser Material Processing Techniques
- Optical and Acousto-Optic Technologies
- Ocular and Laser Science Research
- Plasmonic and Surface Plasmon Research
- Optical Polarization and Ellipsometry
- Spectroscopy and Laser Applications
- Nonlinear Optical Materials Studies
University of Iowa
2021-2025
University of Twente
2016-2024
University of Copenhagen
2019-2024
Tata Institute of Fundamental Research
2010-2023
Photonic Systems (United States)
2015-2019
Photonic qubits are key enablers for quantum-information processing deployable across a distributed quantum network. An on-demand and truly scalable source of indistinguishable single photons is the essential component enabling high-fidelity photonic operations. A main challenge to overcome noise decoherence processes in order reach steep benchmarks on generation efficiency photon indistinguishability required scaling up source. We report realization deterministic single-photon featuring...
Abstract On‐demand single‐photon sources emitting pure and indistinguishable photons at the telecommunication wavelength are critical assets toward deployment of fiber‐based quantum networks. Indeed, single may serve as flying qubits, allowing communication information over long distances. Self‐assembled InAs dots embedded in GaAs constitute an excellent nearly deterministic source high‐quality photons, but vast majority operate 900–950 nm range, precluding their adoption a network. A...
We measure intensity statistics and identify statistical regimes crossovers in random lasers based on nonresonant feedback. A single parameter extracted from an α-stable Levy fit is used to characterize the distributions all regimes. Measurements made over a range of scattering strengths, excitation energies, sample sizes enable us demarcate three corresponding crossovers. An initial subthreshold Gaussian regime abruptly transits into at lasing threshold, which followed by continuous gradual...
We investigate two-photon quantum interference in an opaque scattering medium that intrinsically supports a large number of transmission channels. By adaptive spatial phase modulation the incident wave fronts, photons are directed at targeted speckle spots or output From ${10}^{3}$ experimentally available coupled channels, we select two channels and enhance their to realize equivalent fully programmable $2\ifmmode\times\else\texttimes\fi{}2$ beam splitter. sending pairs single from...
Critical excitation in random lasers under picosecond and nanosecond pumping was experimentally studied. The resulting emission intensity statistics were analyzed using fits to $\ensuremath{\alpha}$-stable distributions. We find that the transition value of $\ensuremath{\alpha}$, tail exponent stable distribution, is a clear indicator threshold lasing. discuss this as an identifier threshold. This definition compared with conventional definitions for threshold, namely, probability lasing...
Planar nanophotonic structures enable broadband, near-unity coupling of emission from quantum dots embedded within, thereby realizing ideal single-photon sources. The efficiency and coherence the source is limited by charge noise, which results in broadening spectrum. We report suppression noise fabricating photonic crystal waveguides a gallium arsenide membrane containing p-i-n diode. Local electrical contacts vicinity minimize leakage current allow fast control (≈4 MHz bandwidth) dot...
Scaling up single-photon sources directly on a chip is fundamental requirement for realizing quantum information protocols that demand scalable, integrated photonic qubits. Integrating multiple emitters in circuit has encountered major roadblocks wavelength disparity and the lack of compact excitation method. The authors demonstrate simultaneous two dots same independent control emitters' wavelengths, enabling two-photon interference. Spectral diffusion not as detrimental to interference...
We examine the dependence of Gaussian-L\'evy transition in random lasers on disorder strength, through experimental and theoretical studies. Experiments are performed samples whose strength varied over almost an order magnitude. It is found that L\'evy regime easily accessed under low excitation when weak, compared to energetically expensive strong disorder. Besides, conditions weak disorder, energy mildly dependent strength. The also progresses rapidly weakly scattering samples. In...
Lévy fluctuations have associated infinities due to diverging moments, a problem that is circumvented by putting restrictions on the magnitude of fluctuations, realizing process called truncated flight. We show perfect manifestation this exotic occurs in coherent random lasers, and it turns out be single underlying explanation for complete statistical behavior nonresonant lasers. A rigorous parameter estimation number summand variables, truncation parameter, power-law exponent carried over...
It is well known that waves incident upon a crystal are transported only over limited distance - the Bragg length before being reflected by interference. Here, we demonstrate how to send much deeper into crystals, studying light in exemplary two-dimensional silicon photonic crystals. By spatially shaping optical wavefronts, observe intensity of laterally scattered light, probes internal energy density, enhanced at tunable away from front surface. The up $100 \times$ compared random...
Photons are the fundamental carriers of classical and quantum information across long distances via optical fibers. Multimode fibers with many transverse modes can support high‐capacity communication through space‐division multiplexing. While spatial correlations in light transmission have been investigated for counteracting mode mixing, less is known about frequency correlations, which critical using ultrashort pulses. This study uses complex wavefront shaping methods to investigate how...
We report on intensity fluctuations of a coherent random laser based incoherent feedback via nonresonant multiple scattering. quantify the spectral line shape in terms correlations an individual spectrum with ensemble-averaged spectrum, which infers signature gain profile medium. These are studied relation to highest modes. evaluate distribution ratio and fractions emission, after independently assessing their statistics. Finally, these graphically represented single scatter plot, centroid...
Precise control of the properties semiconductor quantum dots (QDs) is vital for creating novel devices photonics and advanced opto-electronics. Suitable low QD-densities single QD experiments are challenging to during epitaxy typically found only in limited regions wafer. Here, we demonstrate how conventional molecular beam (MBE) can be used modulate density optically active QDs one- two- dimensional patterns, while still retaining excellent quality. We find that material thickness gradients...
Entanglement is the fuel of advanced quantum technology, enabling, e.g., measurement-based computing and loss-tolerant encoding information. In photonics, entanglement has traditionally been generated probabilistically, requiring massive multiplexing for scaling up to many photons. An alternative approach utilizing emitters in nanophotonic devices can realize deterministic generation entangled However, such sources generate polarization that incompatible with spatial dual-rail qubit employed...
We theoretically investigate quantum interference of two single photons at a lossy asymmetric beam splitter, the most general passive 2×2 optical circuit.The losses in circuit result non-unitary scattering matrix with non-trivial set constraints on elements matrix.Our analysis using noise operator formalism shows that loss allows tunability to an extent not possible lossless splitter.Our theoretical studies support experimental demonstrations programmable highly multimodal systems such as...
The identification of a complete three-dimensional (3D) photonic band gap in real crystals always employs theoretical or numerical models that invoke idealized crystal structures. Thus, this approach is prone to false positives (gap wrongly assigned) negatives missed). Therefore, we propose purely experimental probe the 3D pertains many different classes materials. We study position and polarization-resolved reflectivity spectra inverse woodpile structures consist two perpendicular nanopore...
Boson sampling is a specialized algorithm native to the quantum photonic platform developed for near-term demonstrations of advantage over classical computers. While clear useful applications such pre-fault-tolerance devices are not currently known, reaching regime serves as benchmark hardware. Here, we analyze and detail hardware requirements needed reach with deterministic emitters, promising computing. We elucidate key steps that can be taken in experiments overcome practical constraints...
We demonstrate coherent random lasing from an aerosol of dye-doped microdroplets in air. The is the form a linear array polydisperse, arbitrarily shaped, and randomly spaced with average dimensions about 30 μm. Upon optical excitation, ultranarrow modes were observed emission along axis array, while transverse exhibited intrascatterer resonance peaks. Direct spatiospectral imaging threshold studies confirmed origin peaks to be spatial that extended over polydisperse microdroplets.
We report our studies on exponentially-tempered Lévy sums that explain coherent random lasers based nonresonant feedback. investigate the hierarchy in and identify contribution of extremes over a wide range excitation energies disorder strengths. Subsequently, we carry out experiments which physical manifestation these is revealed. At appropriate gain disorder, manifest as sharp ultranarrow modes spectrum. stronger peaks disappear due to reduced rarity extremes, compounded by decreased...
Encoding information in the position of single photons has no known limits, given infinite resources. Using a heralded single-photon source and spatial light modulator (SLM), we steer to specific positions virtual grid on large-area spatially resolving photon-counting detector (ICCD). We experimentally demonstrate selective addressing any location (symbol) 9072 size (alphabet) achieve 10.5 bit mutual per detected photon between sender receiver. Our results can be useful for...
We have investigated the transport of light through slabs that both scatter and strongly absorb, a situation occurs in diverse application fields ranging from biomedical optics, powder technology, to solid-state lighting. In particular, we study visible wavelength range between 420 700 nm silicone plates filled with YAG:Ce3+ phosphor particles, even re-emit absorbed at different wavelengths. measure total transmission, reflection, ballistic transmission these plates. obtain average single...
We experimentally demonstrate single-mode coherent random lasing in a linear array of monodisperse amplifying microresonators, which behaves as an periodic-on-average system. theoretically analyse the frequency distribution modes under weak and strong configurational disorder. show that tuning microresonator diameter can match interval with gain maximum, thus achieving spectral mode-matching. implement this mode-matched system yields 76% probability restricted to width ∼1.2 nm, offering...
We study the variation of coherent modes in emission a random laser based on nonresonant feedback at critical excitation. A baseline-finding algorithm is applied to separate and incoherent components from complete spectrum. By applying intensity thresholds isolated spectrum, modal density measured as function mode intensity, which shows an exponential decay, corresponding probability amplified extended modes. measure magnitude maximally modes, whose distribution presence equal fraction any...