A5082195576- Cold Atom Physics and Bose-Einstein Condensates
- Photonic Crystal and Fiber Optics
- Advanced Fiber Laser Technologies
- Radio Frequency Integrated Circuit Design
- Quantum, superfluid, helium dynamics
- Quantum Information and Cryptography
- Advanced Frequency and Time Standards
- Random lasers and scattering media
- Atomic and Subatomic Physics Research
- Solid State Laser Technologies
- Laser-Matter Interactions and Applications
- Photonic and Optical Devices
- Quantum optics and atomic interactions
- Analog and Mixed-Signal Circuit Design
- Advanced Optical Sensing Technologies
- Physics of Superconductivity and Magnetism
- Quantum chaos and dynamical systems
- Microwave Engineering and Waveguides
- Advancements in PLL and VCO Technologies
- Optical Network Technologies
- Orbital Angular Momentum in Optics
- Advanced Control Systems Design
- Chaos-based Image/Signal Encryption
- Advancements in Semiconductor Devices and Circuit Design
- Advanced Fiber Optic Sensors
Coherent (United States)
2017-2024
Imam Khomeini International University
2023
University of Tehran
2022
University of Calgary
2011-2017
Islamic Azad University Shahr-e-Rey
2017
Massachusetts Institute of Technology
2009-2012
MIT-Harvard Center for Ultracold Atoms
2009-2012
Oklahoma State University
2005-2010
Georgia Institute of Technology
2007-2009
Oklahoma State University Oklahoma City
2006
Antiresonant hollow-core fibers (AR-HCFs) have opened up exciting possibilities for high-energy and high-power laser delivery because of their exceptionally low nonlinearities high damage thresholds. While these fiber designs offer great potential handling kilowatt-class powers, it is crucial to investigate performance at multi-kW power levels. Until now, transmission narrow-linewidth single-mode lasers levels through a HCF has not been demonstrated, our knowledge. Here, we present the...
We report on the formation of ultracold weakly bound Feshbach molecules 23Na40K, first fermionic molecule that is chemically stable in its absolute ground state. The lifetime nearly degenerate molecular gas exceeds 100 ms vicinity resonance. measured dependence binding energy magnetic field demonstrates open-channel character over a wide range and implies significant singlet admixture. This will enable efficient transfer into vibrational state, resulting Fermi with strong dipolar interactions.
We have created a quantum degenerate Bose-Fermi mixture of 23Na and 40K with widely tunable interactions via broad interspecies Feshbach resonances. Twenty resonances between were identified. The large negative triplet background scattering length causes sharp enhancement the fermion density in presence Bose condensate. As explained asymptotic bound-state model (ABM), this strong leads to series wide observed at low magnetic fields. Our work opens up prospect create chemically stable,...
Individual laser-cooled atoms are delivered on demand from a single atom magneto-optic trap to high-finesse optical cavity using an conveyor. Strong coupling of the with field allows simultaneous cooling and detection individual for time scales exceeding 15 s. The scatter rate is studied as function probe-cavity detuning probe Rabi frequency, experimental results in qualitative agreement theoretical predictions. We demonstrate ability manipulate position relative mode excellent control...
We have created a triply quantum-degenerate mixture of bosonic $^{41}\mathrm{K}$ and two fermionic species $^{40}\mathrm{K}$ $^{6}\mathrm{Li}$. The boson is shown to be an efficient coolant for the fermions, spurring hopes observation superfluids with imbalanced masses. observe multiple heteronuclear Feshbach resonances, in particular wide $s$-wave resonance combination $^{41}\mathrm{K}$-$^{40}\mathrm{K}$, opening up studies strongly interacting isotopic Bose-Fermi mixtures. For large...
This study presents new techniques for implementing continuous-time second-order band-pass filters with high-quality factors and asymmetric slopes. The are centred around the realisation of two non-conventional transfer functions which include non-integer-order Laplacian operator sα; 0<α<1. Four main possible circuit realisations; one based on a frequency-dependent negative resistor (FDNR), another an inductor multiple amplifier biquads (MABs) given verified using Spice experimentally both...
Abstract Emerging and hazardous environmental pollutants like phthalic acid esters (PAEs) are one of the recent concerns worldwide. PAEs considered to have diverse endocrine disrupting effects on human health. Industrial wastewater has been reported as an important environment with high concentrations PAEs. In present study, four short-chain including diallyl phthalate (DAP), diethyl (DEP), dimethyl (DMP), (PA) were selected a substrate for anaerobic fixed film bed reactor (AnFFFBR). The...
We designed and demonstrate a fiber-based amplified spontaneous emission (ASE) source with low spatial coherence, temporal high power per mode. ASE is produced by optically pumping large gain core multimode fiber while minimizing optical feedback to avoid lasing. The provides 270 mW of continuous wave emission, centered at {\lambda}=1055 nm full-width half-maximum bandwidth 74 nm. distributed among as many ~70 modes, enabling efficient speckle suppression when combined spectral compounding....
This paper presents an inductorless 0.13- μm CMOS TIA structure that is a modified version of regulated cascode (RGC) TIA. An immittance converter incorporated to reduce power consumption while increasing transimpedance gain. Measured 3-dB bandwidth 7 GHz, sufficient for 10-Gb/s operation, in the presence 250 fF capacitance at input, representative typical photodiode capacitance. The gain single-stage 50 dBΩ, and group-delay variation less than ±19 ps over bandwidth. circuit occupies active...
This brief presents a novel wide-bandwidth second-order voltage-mode all-pass filter derived from canonical single transistor bandpass filter. The core of the circuit consists only one transistor, two resistors, and energy storage elements. operation proposed is validated experimentally. A implemented in an IBM 0.13-μm CMOS was measured to have 55-ps group delay across 6-GHz bandwidth while consuming 18.5 mW 1.5-V supply. work experimentally demonstrates that operates at multigigahertz...
The key challenge for high-power delivery through optical fibers is overcoming nonlinear effects. To keep a smooth output beam, most techniques mitigating nonlinearities are restricted to single-mode fibers. Moving out of the paradigm, we show experimentally that wavefront-shaping coherent input light highly multimode fiber can increase power threshold stimulated Brillouin scattering (SBS) by an order magnitude, whilst simultaneously controlling beam profile. SBS suppression results from...
We experimentally explore the underlying pseudoclassical phase space structure of quantum $\ensuremath{\delta}$-kicked accelerator. This was achieved by exposing a Bose-Einstein condensate to spatially corrugated potential created pulses an off-resonant standing light wave. For first time accelerator modes were realized in such system. By utilizing narrow momentum distribution we able observe discrete state mode and also directly measure size structures space.
We report on the high resolution photoassociation spectroscopy of a $^{87}\mathrm{Rb}$ spin-1 Bose-Einstein condensate to ${1}_{g}({P}_{3∕2})$ $v=152$ excited molecular states. demonstrate use spin dependent experimentally identify states and their corresponding initial scattering channel. These identifications are in excellent agreement with eigenvalues hyperfine-rotational Hamiltonian. Using observed spectra we estimate change length laser light frequency ranges that maximize...
A CMOS wide-bandwidth first-order current-mode all-pass filter (APF) is discussed. The circuit consists of one transistor, a resistor, grounded inductor, and load. When used with current mirror as the load, exhibits high output impedance, which advantageous from an integration point view enables this configuration to be cascaded circuits. operation proposed experimentally validated. APF implemented in IBM 0.13-μm was measured have pole-zero pair located at 8.32 GHz achieve 55 ps group delay...
We have realized a one-dimensional optical lattice for individual atoms with lifetime $>300\phantom{\rule{0.3em}{0ex}}\mathrm{s}$, which is $5\ifmmode\times\else\texttimes\fi{}$ longer than previously reported. In order to achieve this long lifetime, it necessary laser-cool the briefly every $20\phantom{\rule{0.3em}{0ex}}\mathrm{s}$ overcome heating due technical fluctuations in trapping potential. Without cooling, we observe negligible atom loss within first followed by an exponential...
A broadband RF delay-and-sum (DAS) beamformer, which employs wide-band CMOS all-pass filters for achieving the desired time delays, is discussed in this work. The use of eliminates need I/Q mixers and transmission line-based delay stages used previously reported DAS beamformers. proposed filter can achieve approximately linear-phase across GHz-range frequencies, amendable beamforming. section beamformer was designed simulated an array 4 antennas, with signal direction arrival 11° from...
We present the development of a high-power laser source operating at 532 nm produced by frequency doubling Ybdoped fiber amplifier. The amplifier has multistage design, and uses large mode area Yb-doped fibers as gain medium to produce > 2 kW power 1064 nm. design is optimized reduce non-linear effects, operates linewidths narrow 45 GHz. By focusing output into an LBO crystal, more than 1 light produced. Single pass conversion efficiencies high 54% are achieved providing unique combination...
The effect of dielectric barrier discharge (DBD) plasma treatment was studied on the surface characteristics and coating performance transparent epoxy resin particleboard (PB) medium-density fiberboard (MDF). performed at three energies (10, 15, 20 kW) distances from nozzle 20, 30 mm). Analyzing samples by Fourier transform infrared (FTIR) spectroscopy X-ray photoelectron (XPS) indicated changes their chemical structure means treatment. contact angle study showed a significant increase in...
Novel CMOS wide-bandwidth 1 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">st</sup> - and 2 xmlns:xlink="http://www.w3.org/1999/xlink">nd</sup> -order current-mode allpass filters are proposed in this paper. The filter consists of only one transistor, two resistors grounded inductor. An addition capacitor converts the into a filter. A with delay approximately 33 ps pole-zero location 10 GHz is designed to confirm circuit operation. pair...
We report the observation of high-order resonances quantum δ-kicked accelerator using a BEC kicked by standing wave light. The signature these is existence modes. For first time modes were seen near 1/2, 2/3 and 1/3 half-Talbot time. Using enabled internal momentum state structure to be studied for This has many similarities that present in fractional Talbot effect. theory this system based on rephasing orders apply it predict behavior around resonance any order.
A 0.96-to-5.1GHz 4-element antenna array is described. The beamformer designed in 0.13-μm CMOS using a delay-and-sum (DAS) architecture enhanced with spatially analog IIR filter for sidelobe reduction. DAS portion based on novel delay element that provides 82-ps range and consumes 6.15 mW of power. circuit measured to achieve levels -22 dBc, which 10-dB improvement over prior art.