scholarly journals Controllable Fast and Slow Light in Photonic-Molecule Optomechanics with Phonon Pump

Micromachines ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1074
Author(s):  
Huajun Chen
Keyword(s):  
Numerical Simulations ◽  
Laser Field ◽  
Slow Light ◽  
Light Transmission ◽  
Pump Laser ◽  
Probe Laser ◽  
Probe Field ◽  
Optomechanical System ◽  
Optical Output ◽  
Fast Light

We theoretically investigate the optical output fields of a photonic-molecule optomechanical system in an optomechanically induced transparency (OMIT) regime, in which the optomechanical cavity is optically driven by a strong pump laser field and a weak probe laser field and the mechanical mode is driven by weak coherent phonon driving. The numerical simulations indicate that when the driven frequency of the phonon pump equals the frequency difference of the two laser fields, we show an enhancement OMIT where the probe transmission can exceed unity via controlling the driving amplitude and pump phase of the phonon driving. In addition, the phase dispersion of the transmitted probe field can be modified for different parametric regimes, which leads to a tunable delayed probe light transmission. We further study the group delay of the output probe field with numerical simulations, which can reach a tunable conversion from slow to fast light with the manipulation of the pump laser power, the ratio parameter of the two cavities, and the driving amplitude and phase of the weak phonon pump.

scholarly journals TRANSIENT AND STEADY-STATE ABSORPTIONS OF A WEAK PROBE FIELD IN A COUPLED DOUBLE QUANTUM-WELL STRUCTURE

2009 ◽  
Vol 23 (18) ◽  
pp. 2215-2227 ◽  
Author(s):  
WEN-XING YANG ◽  
JIN XU ◽  
RAY-KUANG LEE
Keyword(s):  
Steady State ◽  
Quantum Well ◽  
Laser Field ◽  
Probe Laser ◽  
Double Quantum ◽  
Probe Field ◽  
Two Photon ◽  
State Process ◽  
Double Quantum Well ◽  
Efficient Scheme

We propose and analyze an efficient scheme for suppressing the absorption of a weak probe field based on intersubband transitions in a four-level asymmetric coupled quantum well (CQW) driven coherently by a probe laser field and a control laser field. We study the steady-state process analytically and numerically, and our results show that the probe absorption can be completely eliminated under the condition of Raman resonance (i.e. two-photon detuning is zero). Besides, we can observe one transparency window without requiring one- or two-photon detuning to exactly vanish. This investigation may provide a possible scheme for EIT in solids by using the CQW.

CROSSOVER FROM SPONTANEOUSLY GENERATED COHERENCE TO AUTLER–TOWNES SPLITTING IN THREE-LEVEL ATOMIC SYSTEMS

2013 ◽  
Vol 27 (14) ◽  
pp. 1350065
Author(s):  
QIONG DU ◽  
CHAO HANG ◽  
GUOXIANG HUANG
Keyword(s):  
Absorption Spectrum ◽  
Laser Field ◽  
Type System ◽  
Type Systems ◽  
Probe Laser ◽  
Residue Theorem ◽  
Probe Field ◽  
Atomic Systems ◽  
Spontaneously Generated Coherence ◽  
Spectrum Decomposition

We investigate spontaneously generated coherence (SGC) and Autler–Townes Splitting (ATS) in various three-level systems. Through detailed analytical calculations on absorption spectrum of probe laser field, we show that in V-type system the SGC can completely eliminate the absorption of the probe field and at the same time significantly reduce the group velocity. By using residue theorem and spectrum decomposition method, we prove that there exists a crossover from SGC to ATS for both cold and warm atoms when the magnitude of SGC is changed. Different contributions of SGC and ATS to probe-field absorption spectrum are clearly clarified in different parameter regions. In addition, our results show that there is no SGC and hence no SGC-ATS crossover in Λ- and Ξ-type systems.

scholarly journals Controllable Fast and Slow Light in the Hybrid Nanomechanical Resonator System

2021 ◽  
Author(s):  
Hua-Jun Chen
Keyword(s):  
Absorption Spectra ◽  
Slow Light ◽  
Fano Resonances ◽  
Light Effect ◽  
Probe Field ◽  
Nanomechanical Resonator ◽  
Phase Dispersion ◽  
Resonator System ◽  
Fast Light ◽  
Slow And Fast Light

Abstract We propose a hybrid nanomechanical resonator (NR) system, where a NR coupled to an embedded quantum dot (QD) driven by two-tone fields is also coupled to another NR via the Coulomb interaction, and investigate the absorption spectra of the probe field under both the condition of resonance and off-resonance. The absorption spectra in resonance presents a means to determine the coupling strength of the two NRs. In the off-resonance, the absorption spectra can exhibit double Fano resonance, and the positions of the double Fano resonances are related to the interaction of the two NRs, the frequencies of the NRs, and the pump detuning. Furthermore, the double Fano resonances are accompanied by the rapid normal phase dispersion, which indicates the slow- and fast-light effect. We can obtain that the group velocity index is tunable by the interaction between the two NRs, the detuning, and the different resonator frequencies, which can reach the conversion from the fast light to slow light.

Carbon Overcoat Loss From the Surface of a Heat Assisted Magnetic Storage Disk due to Laser Irradiation

2013 ◽  
Author(s):  
Paul M. Jones ◽  
Joachim Ahner ◽  
Christopher L. Platt ◽  
Huan Tang ◽  
Julius Hohlfeld
Keyword(s):  
Curie Temperature ◽  
Laser Power ◽  
Single Point ◽  
Magnetic Layer ◽  
Pump Laser ◽  
Probe Laser ◽  
Magnetic Storage ◽  
Carbon Overcoat ◽  
Fept Alloy ◽  
The Media

A pump-probe experimental technique that incorporated a 527nm wavelength pump laser and a 476nm probe laser was applied to a magnetic storage disk having a magnetic layer comprised of a FePt alloy and coated with a hydrogenated carbon overcoat (COC). The pump laser power was systematically increased while sweeping the applied field with an electromagnet to observe the temperature dependent magnetization, which is proportional to the change in the polarization of the reflected beam. In this way the laser power required to heat the media to the Curie temperature (Tc) was determined, with the Curie temperature of the media determined from a separate magnetometry measurement. Such a single point laser power-to-media temperature calibration allowed the determination of the media temperature over a small laser power range near Tc. The carbon over-coated FePt media was then irradiated for varying durations at temperatures pertinent to a Heat Assisted Magnetic Recording (HAMR) device [1]. The COC surface topography and carbon bonding structure within each irradiated zone was probed with AFM and micro-spot Raman. A subtle, systematic temperature and duration dependent change in the COC was observed. With increasing temperature and duration, the Raman D-peak became increasingly pronounced, signaling an increase of the sp2 (disorder) content in the film in the irradiated region. At incrementally higher temperatures, the loss of the carbon overcoat becomes apparent as a shallow depression in the COC film in the irradiated area. A clearer picture of the possible sensitivity and kinetics of the loss of COC on the HAMR media surface was obtained by measuring its loss over a range of irradiation temperatures and durations. The activation energy and COC loss rate were obtained and a possible mechanism for COC failure-loss was discussed within the bounds of the operating HAMR device [2].

scholarly journals Unidirectional Slow Light Transmission in Heterostructure Photonic Crystal Waveguide

2018 ◽  
Vol 8 (10) ◽  
pp. 1858 ◽  
Author(s):  
Qiuyue Zhang ◽  
Xun Li
Keyword(s):  
Photonic Crystal ◽  
Slow Light ◽  
Environmental Changes ◽  
Light Transmission ◽  
Square Lattice ◽  
Manufacturing Defects ◽  
Interfacial Defects ◽  
Waveguide Design ◽  
Light Waveguide ◽  
Backward Propagation

In conventional photonic crystal systems, extrinsic scattering resulting from random manufacturing defects or environmental changes is a major source of loss that causes performance degradation, and the backscattering loss is amplified as the group velocity slows down. In order to overcome the limitations in slow light systems, we propose a backscattering-immune slow light waveguide design. The waveguide is based on an interface between a square lattice of magneto-optical photonic crystal with precisely tailored rod radii of the first two rows and a titled 45 degrees square lattice of Alumina photonic crystal with an aligned band gap. High group indices of 77, 68, 64, and 60 with the normalized frequency bandwidths of 0.444%, 0.481%, 0.485%, and 0.491% are obtained, respectively. The corresponding normalized delay-bandwidth products remain around 0.32 for all cases, which are higher than previously reported works based on rod radius adjustment. The robustness for the edge modes against different types of interfacial defects is observed for the lack of backward propagation modes at the same frequencies as the unidirectional edge modes. Furthermore, the transmission direction can be controlled by the sign of the externally applied magnetic field normal to the plane.

Tunable slow light in a quadratically coupled optomechanical system

2013 ◽  
Vol 46 (2) ◽  
pp. 025501 ◽  
Author(s):  
Xiao-Gui Zhan ◽  
Liu-Gang Si ◽  
An-Shou Zheng ◽  
Xiaoxue Yang
Keyword(s):  
Slow Light ◽  
Optomechanical System

scholarly journals Clocked atom delivery to a photonic crystal waveguide

2018 ◽  
Vol 116 (2) ◽  
pp. 456-465 ◽  
Author(s):  
A. P. Burgers ◽  
L. S. Peng ◽  
J. A. Muniz ◽  
A. C. McClung ◽  
M. J. Martin ◽  
...  
Keyword(s):  
Photonic Crystal ◽  
Numerical Simulations ◽  
Optical Trap ◽  
Atomic Motion ◽  
Optical Fields ◽  
Probe Field ◽  
Guided Mode ◽  
Atomic Medium ◽  
Quantitative Understanding ◽  
Spatially Varying

Experiments and numerical simulations are described that develop quantitative understanding of atomic motion near the surfaces of nanoscopic photonic crystal waveguides (PCWs). Ultracold atoms are delivered from a moving optical lattice into the PCW. Synchronous with the moving lattice, transmission spectra for a guided-mode probe field are recorded as functions of lattice transport time and frequency detuning of the probe beam. By way of measurements such as these, we have been able to validate quantitatively our numerical simulations, which are based upon detailed understanding of atomic trajectories that pass around and through nanoscopic regions of the PCW under the influence of optical and surface forces. The resolution for mapping atomic motion is roughly 50 nm in space and 100 ns in time. By introducing auxiliary guided-mode (GM) fields that provide spatially varying AC Stark shifts, we have, to some degree, begun to control atomic trajectories, such as to enhance the flux into the central vacuum gap of the PCW at predetermined times and with known AC Stark shifts. Applications of these capabilities include enabling high fractional filling of optical trap sites within PCWs, calibration of optical fields within PCWs, and utilization of the time-dependent, optically dense atomic medium for novel nonlinear optical experiments.

Tunable slow and fast light in an atom-assisted optomechanical system with a mechanical pump

2020 ◽  
Vol 456 ◽  
pp. 124605 ◽  
Author(s):  
Cui-Ming Han ◽  
Xin Wang ◽  
Hao Chen ◽  
Hong-Rong Li
Keyword(s):  
Optomechanical System ◽  
Mechanical Pump ◽  
Fast Light ◽  
Slow And Fast Light
Sign in / Sign up

Export Citation Format

Share Document