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

Optics Express

Superluminal Raman laser with enhanced cavity length sensitivity

Zifan Zhou, Minchuan Zhou, M. S. Shahriar

Published Oct 1, 2019• 17 citations
Publisher

Abstract

We demonstrate experimentally a superluminal ring laser based on optically pumped Raman gain, and a self-pumped Raman depletion for producing anomalous dispersion, employing two isotopes of rubidium. By fitting the experiment data with the theoretical model, we infer that the spectral sensitivity of the superluminal Raman laser to cavity length change is enhanced by a factor of more than a thousand, compared to a conventional laser.

DOI
10.1364/oe.27.029738

Related papers

A Superluminal Raman Laser with Enhanced Cavity Length Sensitivity

Zifan Zhou, Minchuan Zhou, M. S. Shahriar

We demonstrate experimentally an optically pumped Raman laser with a self-pumped Raman depletion employing two isotopes of rubidium, achieving an inferred spectral sensitivity to cavity length change by a factor of more than a thousand.

Conference on Lasers and Electro-Optics•Jan 1, 2019•0 citations

A Superluminal Raman Laser with Enhanced Cavity Length Sensitivity

Zifan Zhou, Minchuan Zhou, M. S. Shahriar

We demonstrate experimentally an optically pumped Raman laser with a self-pumped Raman depletion employing two isotopes of rubidium, achieving an inferred spectral sensitivity to cavity length change by a factor of more than a thousand.

Conference on Lasers and Electro-Optics•May 5, 2019•0 citations

Observation of a highly superluminal laser employing optically pumped Raman gain and depletion

Zifan Zhou, Nicholas Condon, Devin Hileman +1 more

In this paper, we report a Raman laser which is extremely sensitive to a variation of the cavity length, using a scheme employing two stable isotopes of Rb. One isotope is used for producing a broad gain spectrum via the optically pumped Raman gain process, while the other is used for producing a narrow dip via the optically pumped Raman depletion process. By tuning the frequencies of the two Raman pumps, the center frequencies of the gain and dip can be aligned to the same frequency. This approach allows tuning of the gain and dip parameters independently over a broad range of operating conditions. With such a configuration, we can produce a negative dispersion around the two-photon resonance frequency in the vapor cell, which leads to a group index that is close to zero. By theoretically matching the experimental observations, we can infer that the sensitivity of such laser is enhanced by a factor of more than 2800, which is nearly a factor of three larger than the highest value reported previously using a different approach.

Optics Express•Feb 3, 2022•6 citations

Enhanced sensing in a double-Raman superluminal ring laser

Tony Abi-Salloum, M. S. Shahriar

We investigate the feasibility of realizing a superluminal ring laser with enhanced sensitivity by using the gain produced via double-Raman pumping in an inverted three-level system. If the laser cavity is tuned to the center between the two gain peaks produced in such a system, it is expected to experience an effective negative dispersion, which can be tuned to the condition necessary for enhancing the sensitivity of the laser frequency to a change in the cavity length. Using a model of two idealized, independent Lorentzian gains, we solve the laser equations to show the enhancement of sensitivity. We then extend our analysis to calculate the gain profile in a real lambda system. Unlike the idealized system mentioned above, where the dual gain peaks are modeled as two adjacent Lorentzians in a manner that ignores the relative coherence between the Raman pumps, we present a more accurate model where this coherence is not neglected. As such, the Hamiltonian remains time dependent after making the rotating wave transformation. Using an approximation --- valid for practical systems --- where higher order terms in the density matrix are neglected, we determine the gain experienced by a weak probe beam. Numerical techniques are needed to incorporate the resulting gain and dispersion profiles into the laser equation to determine accurately the behavior of the superluminal laser. This work will be carried out in the near future. Experimental realization of a superluminal laser based on this approach may prove to be easier than other approaches proposed previously.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Mar 6, 2013•0 citations

Demonstration of a superluminal laser using electromagnetically induced transparency in Raman gain

Zifan Zhou, Ruoxi Zhu, Yael Sternfeld +3 more

We report the realization of a superluminal laser in which the dip in the gain profile necessary for anomalous dispersion is produced via electromagnetically induced transparency caused by the optical pumping laser. This laser also creates the ground state population inversion necessary for generating Raman gain. Compared to a conventional Raman laser with similar operating parameters but without the dip in the gain profile, the spectral sensitivity of this approach is explicitly demonstrated to be enhanced by a factor of ∼12.7. Compared to an empty cavity, the peak value of the sensitivity enhancement factor under optimal operation parameters is inferred to be ∼360.

Optics Express•Mar 21, 2023•6 citations

Electromagnetically induced transparency in Raman gain for realizing a superluminal ring laser

Yael Sternfeld, Zifan Zhou, Jacob Scheuer +1 more

We present a technique for realizing a superluminal ring laser with controllable sensitivity enhancement factor using a single isotope of rubidium vapor by producing electromagnetically induced transparency (EIT) in Raman gain via optical pumping.

Frontiers in Optics•Jan 1, 2020•1 citation
We demonstrate experimentally a superluminal ring laser based on optically pumped Raman gain, and a self-pumped Raman depletion for producing anomalous dispersion, employing two isotopes of rubidium. By fitting the experiment data with the theoretical model, we infer that the spectral sensitivity of the superluminal Raman laser to cavity length change is enhanced by a factor of more than a thousand, compared to a conventional laser.
In this paper, we report a Raman laser which is extremely sensitive to a variation of the cavity length, using a scheme employing two stable isotopes of Rb. One isotope is used for producing a broad gain spectrum via the optically pumped Raman gain process, while the other is used for producing a narrow dip via the optically pumped Raman depletion process. By tuning the frequencies of the two Raman pumps, the center frequencies of the gain and dip can be aligned to the same frequency. This approach allows tuning of the gain and dip parameters independently over a broad range of operating conditions. With such a configuration, we can produce a negative dispersion around the two-photon resonance frequency in the vapor cell, which leads to a group index that is close to zero. By theoretically matching the experimental observations, we can infer that the sensitivity of such laser is enhanced by a factor of more than 2800, which is nearly a factor of three larger than the highest value reported previously using a different approach.
We investigate the feasibility of realizing a superluminal ring laser with enhanced sensitivity by using the gain produced via double-Raman pumping in an inverted three-level system. If the laser cavity is tuned to the center between the two gain peaks produced in such a system, it is expected to experience an effective negative dispersion, which can be tuned to the condition necessary for enhancing the sensitivity of the laser frequency to a change in the cavity length. Using a model of two idealized, independent Lorentzian gains, we solve the laser equations to show the enhancement of sensitivity. We then extend our analysis to calculate the gain profile in a real lambda system. Unlike the idealized system mentioned above, where the dual gain peaks are modeled as two adjacent Lorentzians in a manner that ignores the relative coherence between the Raman pumps, we present a more accurate model where this coherence is not neglected. As such, the Hamiltonian remains time dependent after making the rotating wave transformation. Using an approximation --- valid for practical systems --- where higher order terms in the density matrix are neglected, we determine the gain experienced by a weak probe beam. Numerical techniques are needed to incorporate the resulting gain and dispersion profiles into the laser equation to determine accurately the behavior of the superluminal laser. This work will be carried out in the near future. Experimental realization of a superluminal laser based on this approach may prove to be easier than other approaches proposed previously.
We report the realization of a superluminal laser in which the dip in the gain profile necessary for anomalous dispersion is produced via electromagnetically induced transparency caused by the optical pumping laser. This laser also creates the ground state population inversion necessary for generating Raman gain. Compared to a conventional Raman laser with similar operating parameters but without the dip in the gain profile, the spectral sensitivity of this approach is explicitly demonstrated to be enhanced by a factor of ∼12.7. Compared to an empty cavity, the peak value of the sensitivity enhancement factor under optimal operation parameters is inferred to be ∼360.