Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Tunable Optical True-Time Delay Devices Would Exploit EIT

Igor K. Kulikov, L.D. DiDomenico, Hwang Lee

Published Oct 1, 2004• 0 citations
OpenAlex

Abstract

Tunable optical true-time delay devices that would exploit electromagnetically induced transparency (EIT) have been proposed. Relative to prior true-time delay devices (for example, devices based on ferroelectric and ferromagnetic materials) and electronically controlled phase shifters, the proposed devices would offer much greater bandwidths. In a typical envisioned application, an optical pulse would be modulated with an ultra-wideband radio-frequency (RF) signal that would convey the information that one seeks to communicate, and it would be required to couple differently delayed replicas of the RF signal to the radiating elements of a phased-array antenna. One or more of the proposed devices would be used to impose the delays and/or generate the delayed replicas of the RF-modulated optical pulse. The beam radiated or received by the antenna would be steered by use of a microprocessor-based control system that would adjust operational parameters of the devices to tune the delays to the required values. EIT is a nonlinear quantum optical interference effect that enables the propagation of light through an initially opaque medium. A suitable medium must have, among other properties, three quantum states (see Figure 1): an excited state (state 3), an upper ground state (state 2), and a lower ground state (state 1). These three states must form a closed system that exhibits no decays to other states in the presence of either or both of two laser beams: (1) a probe beam having the wavelength corresponding to the photon energy equal to the energy difference between states 3 and 1; and (2) a coupling beam having the wavelength corresponding to the photon energy equal to the energy difference between states 3 and 2. The probe beam is the one that is pulsed and modulated with an RF signal.

Related papers

Frequency-tuned continuous true-time delay by optical coherent transient technology

K.D. Merkel, William Randall Babbitt

Summary form only given. A practical device creating a variable RF true-time delay (TTD) for signals on an optical carrier would be useful in array antennas. An optical coherent transient (OCT)-TTD device could provide high-resolution delays (/spl sim/1 ps) over a wide range (/spl sim/1 /spl mu/s), for high bandwidth signals (/spl sim/10 GHz) with currently available materials. In previously demonstrated OCT-TTD devices, two optical pulses separated in time and space program a delay in an absorbing medium as a spatial-spectral grating on an inhomogeneously broadened transition (IBT). In the paper, we experimentally demonstrate widely tunable OCT-TTD of a continuous optical data stream without changing the timing between the programming pulses.

Conference on Lasers and Electro-Optics•Jan 20, 2003•0 citations

Attenuation, Delay and Noise properties of light slowed by Electromagnetically Induced Transparency

Kerry B. Burke

Electromagnetically Induced Transparency is an effect that allows light to propagate through an otherwise opaque material. Due to the dispersion properties of the EIT system, it also slows the information carried on the sideband frequencies of a light beam. The effect can also be used to store information in an atomic medium. It was therefore proposed that EIT systems can be applied in optical cicuits, specifically with regard to quantum information processing where it is necessary to delay, or store quantum states of light. Hence it is necessary to understand how EIT systems influence the quantum state of a light beam and whether EIT systems can ever have the potential to delay and store quantum information at the quantum noise limit. ¶ This thesis examines the transfer of an optical signal at the sideband frequencies through an EIT medium. A comprehensive characterisation of an EIT system in terms of delay and signal transmission is performed. This measurement technique provides data on EIT performance over a range of signal frequencies and a range of experimental parameters. Experiments were conducted with both pure Rubidium vapour and Rubidium vapour mixed with a noble gas. ¶ Studies have been made into a new system of measurement that will allow delay, attenuation and added noise spectra to be assessed via a single-shot measurement.

•Jan 1, 2006•0 citations

EFFECTS OF MODULATION SCHEMES ON OPTICAL PULSES TRANSITING AN ELECTROMAGNETICALLY INDUCED TRANSPARENT MEDIUM

Wachter, Christian F.

This thesis investigates the result of modulation schemes in electromagnetically induced transparency (EIT) in rubidium vapor. Through the process of EIT, a control beam can be used to change the optical properties of a medium experienced by a probe field, generating a transparency window. The corresponding change in index of refraction results in slowed group velocity while the beam propagates through the medium. Modulation is used to transmit a message signal through a medium. In classical systems, this entails converting data into a radio frequency by adding a message to an electronic or optical carrier signal. The properties of EIT, light-slowing, and their impacts on a probe pulse with modulation will be confirmed through a detailed semi-classical analysis and by experimental observation.

•Sep 1, 2023•0 citations

Optical precursors via spontaneously generated coherence

Nuo Ba, Lei Wang, Wang Hai-Hua +3 more

Optical precursors were first studied by Sommerfield and Brillouin in 1914 to resolve the apparent contradictions between fast light propagation and the theory of relativity. They showed theoretically that the front edge of a step-modulated pulse does not interact with the medium and always travels at c because the dispersive material has a finite response time to the optical pulse. The past experimental studies of precursors in classical pulse propagation were always focused on an opaque medium with single or multiple Lorentz absorption lines. In these cases, the precursor signal cannot be separated from the main pulse or otherwise the main field is absorbed. However, the electromagnetically induced transparency (EIT) technique was successfully used to separate precursors from the main pulse due to the slow-light effect in cold atoms. The EIT refers to the absorption suppression or elimination of a probe field through atomic coherence in a certain medium dressed by a strong coupling field. In this paper, a four-level double-lambda atomic system with two upper states coupled to the excited state is explored to separate optical precursors from a square-modulated laser pulse with the effect of spontaneously generated coherence (SGC). The SGC effect occurs in the process of spontaneous emission, in which the atom decays from closely placed upper levels to a single ground level. The quantum interference between the decay channels takes place, which leads to decay induced transparency, thus enhancing the Kerr nonlinearity and amplification without inversion. With the assistance of spontaneously generated coherence, an EIT window appears with steep normal dispersion when the trigger field is far from resonance. Then we can obtain the optical precursors which are separated from the main pulse due to the slow-light effects in the EIT window. In the absence of SGC, the main pulse is absorbed by an opaque medium with Lorentz absorptive lines, so the slow-light effect could not take place. In addition, we obtain the stacked optical precursors with the input probe field amplitude or phase modulated by designing a series of square pulses. For the amplitude modulation case, the peak power reaches about 4.5 times that of the input pulse. With the phase modulation we obtain a transient pulse with a peak power of 14 times that of the input, as a result of constructive interference between the stacked precursors and main field. We expect these findings to be instructive in devising optical devices for optical communication, detection and medical imaging among other applications.

Acta Physica Sinica•Jan 1, 2016•1 citation

Brillouin scattering induced transparency and generation of slow and fast light

Jun Hwan Kim

Electromagnetically induced transparency (EIT) is generation of a narrow window in which electromagnetic field absorption is inhibited. Experimentally, a probe tuned to a certain absorption wavelength is allowed to transmit through a gaseous vapor only in the presence of a second control laser. In other words, a probe is forbidden to cause an excitation from one energy level to another through coherent coupling with a third, intermediate energy level that creates an interference pathway. In this study, Brillouin scattering analogue of EIT is demonstrated using the two optical modes that are coupled through a phase matched acoustic mode. The coherent coupling of two energy levels is emulated by the acousto-optic interaction of Brillouin scattering. The probe phase response is analyzed to estimate BSIT's effect on the velocity of light pulse. As BSIT modifies the dispersion of light, it is understood as either slowing or advancing light propagation depending on the sign of the slope of the probe phase response. Lastly, the non-reciprocity of Brillouin scattering is theoretically considered. The non-reciprocity, or a break in time reversal symmetry, is a unique property of Brillouin scattering process due to the traveling surface acoustic wave which is used for phase matching the optical modes. Therefore, BSIT can be used for applications such as optical isolation while no other transparency systems can.

•Sep 16, 2014•0 citations

Experimental demonstration of slow and superluminal light in semiconductor optical amplifiers

Bala Pesala, Zhangyuan Chen, Alexander V. Uskov +1 more

Tunable delays in semiconductor optical amplifiers are achieved via four wave mixing between a strong pump beam and a modulated probe beam. The delay of the probe beam can be controlled both electrically, by changing the SOA bias, and optically, by varying the pump power or the pump-probe detuning. For sinusoidal modulated signal at 0.5 GHz, a tunable delay of 1.6 ns is achieved. This corresponds to a RF phase change of 1.6 pi. For 1.3 ns optical pulses propagating through the SOA a delay of 0.59 ns is achieved corresponding to a delay-bandwidth product exceeding 0.45. For both the cases, slow light and superluminal light are observed as the pump-probe detuning is varied.

Optics Express•Jan 1, 2006•35 citations
Tunable optical true-time delay devices that would exploit electromagnetically induced transparency (EIT) have been proposed. Relative to prior true-time delay devices (for example, devices based on ferroelectric and ferromagnetic materials) and electronically controlled phase shifters, the proposed devices would offer much greater bandwidths. In a typical envisioned application, an optical pulse would be modulated with an ultra-wideband radio-frequency (RF) signal that would convey the information that one seeks to communicate, and it would be required to couple differently delayed replicas of the RF signal to the radiating elements of a phased-array antenna. One or more of the proposed devices would be used to impose the delays and/or generate the delayed replicas of the RF-modulated optical pulse. The beam radiated or received by the antenna would be steered by use of a microprocessor-based control system that would adjust operational parameters of the devices to tune the delays to the required values. EIT is a nonlinear quantum optical interference effect that enables the propagation of light through an initially opaque medium. A suitable medium must have, among other properties, three quantum states (see Figure 1): an excited state (state 3), an upper ground state (state 2), and a lower ground state (state 1). These three states must form a closed system that exhibits no decays to other states in the presence of either or both of two laser beams: (1) a probe beam having the wavelength corresponding to the photon energy equal to the energy difference between states 3 and 1; and (2) a coupling beam having the wavelength corresponding to the photon energy equal to the energy difference between states 3 and 2. The probe beam is the one that is pulsed and modulated with an RF signal.
Summary form only given. A practical device creating a variable RF true-time delay (TTD) for signals on an optical carrier would be useful in array antennas. An optical coherent transient (OCT)-TTD device could provide high-resolution delays (/spl sim/1 ps) over a wide range (/spl sim/1 /spl mu/s), for high bandwidth signals (/spl sim/10 GHz) with currently available materials. In previously demonstrated OCT-TTD devices, two optical pulses separated in time and space program a delay in an absorbing medium as a spatial-spectral grating on an inhomogeneously broadened transition (IBT). In the paper, we experimentally demonstrate widely tunable OCT-TTD of a continuous optical data stream without changing the timing between the programming pulses.
Electromagnetically Induced Transparency is an effect that allows light to propagate through an otherwise opaque material. Due to the dispersion properties of the EIT system, it also slows the information carried on the sideband frequencies of a light beam. The effect can also be used to store information in an atomic medium. It was therefore proposed that EIT systems can be applied in optical cicuits, specifically with regard to quantum information processing where it is necessary to delay, or store quantum states of light. Hence it is necessary to understand how EIT systems influence the quantum state of a light beam and whether EIT systems can ever have the potential to delay and store quantum information at the quantum noise limit. ¶ This thesis examines the transfer of an optical signal at the sideband frequencies through an EIT medium. A comprehensive characterisation of an EIT system in terms of delay and signal transmission is performed. This measurement technique provides data on EIT performance over a range of signal frequencies and a range of experimental parameters. Experiments were conducted with both pure Rubidium vapour and Rubidium vapour mixed with a noble gas. ¶ Studies have been made into a new system of measurement that will allow delay, attenuation and added noise spectra to be assessed via a single-shot measurement.
This thesis investigates the result of modulation schemes in electromagnetically induced transparency (EIT) in rubidium vapor. Through the process of EIT, a control beam can be used to change the optical properties of a medium experienced by a probe field, generating a transparency window. The corresponding change in index of refraction results in slowed group velocity while the beam propagates through the medium. Modulation is used to transmit a message signal through a medium. In classical systems, this entails converting data into a radio frequency by adding a message to an electronic or optical carrier signal. The properties of EIT, light-slowing, and their impacts on a probe pulse with modulation will be confirmed through a detailed semi-classical analysis and by experimental observation.
Optical precursors were first studied by Sommerfield and Brillouin in 1914 to resolve the apparent contradictions between fast light propagation and the theory of relativity. They showed theoretically that the front edge of a step-modulated pulse does not interact with the medium and always travels at c because the dispersive material has a finite response time to the optical pulse. The past experimental studies of precursors in classical pulse propagation were always focused on an opaque medium with single or multiple Lorentz absorption lines. In these cases, the precursor signal cannot be separated from the main pulse or otherwise the main field is absorbed. However, the electromagnetically induced transparency (EIT) technique was successfully used to separate precursors from the main pulse due to the slow-light effect in cold atoms. The EIT refers to the absorption suppression or elimination of a probe field through atomic coherence in a certain medium dressed by a strong coupling field. In this paper, a four-level double-lambda atomic system with two upper states coupled to the excited state is explored to separate optical precursors from a square-modulated laser pulse with the effect of spontaneously generated coherence (SGC). The SGC effect occurs in the process of spontaneous emission, in which the atom decays from closely placed upper levels to a single ground level. The quantum interference between the decay channels takes place, which leads to decay induced transparency, thus enhancing the Kerr nonlinearity and amplification without inversion. With the assistance of spontaneously generated coherence, an EIT window appears with steep normal dispersion when the trigger field is far from resonance. Then we can obtain the optical precursors which are separated from the main pulse due to the slow-light effects in the EIT window. In the absence of SGC, the main pulse is absorbed by an opaque medium with Lorentz absorptive lines, so the slow-light effect could not take place. In addition, we obtain the stacked optical precursors with the input probe field amplitude or phase modulated by designing a series of square pulses. For the amplitude modulation case, the peak power reaches about 4.5 times that of the input pulse. With the phase modulation we obtain a transient pulse with a peak power of 14 times that of the input, as a result of constructive interference between the stacked precursors and main field. We expect these findings to be instructive in devising optical devices for optical communication, detection and medical imaging among other applications.
Electromagnetically induced transparency (EIT) is generation of a narrow window in which electromagnetic field absorption is inhibited. Experimentally, a probe tuned to a certain absorption wavelength is allowed to transmit through a gaseous vapor only in the presence of a second control laser. In other words, a probe is forbidden to cause an excitation from one energy level to another through coherent coupling with a third, intermediate energy level that creates an interference pathway. In this study, Brillouin scattering analogue of EIT is demonstrated using the two optical modes that are coupled through a phase matched acoustic mode. The coherent coupling of two energy levels is emulated by the acousto-optic interaction of Brillouin scattering. The probe phase response is analyzed to estimate BSIT's effect on the velocity of light pulse. As BSIT modifies the dispersion of light, it is understood as either slowing or advancing light propagation depending on the sign of the slope of the probe phase response. Lastly, the non-reciprocity of Brillouin scattering is theoretically considered. The non-reciprocity, or a break in time reversal symmetry, is a unique property of Brillouin scattering process due to the traveling surface acoustic wave which is used for phase matching the optical modes. Therefore, BSIT can be used for applications such as optical isolation while no other transparency systems can.
Tunable delays in semiconductor optical amplifiers are achieved via four wave mixing between a strong pump beam and a modulated probe beam. The delay of the probe beam can be controlled both electrically, by changing the SOA bias, and optically, by varying the pump power or the pump-probe detuning. For sinusoidal modulated signal at 0.5 GHz, a tunable delay of 1.6 ns is achieved. This corresponds to a RF phase change of 1.6 pi. For 1.3 ns optical pulses propagating through the SOA a delay of 0.59 ns is achieved corresponding to a delay-bandwidth product exceeding 0.45. For both the cases, slow light and superluminal light are observed as the pump-probe detuning is varied.