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

Physical Review A

Optical continua generation in a coherently prepared Raman medium

Roman L. Kolesov

Published Nov 19, 2001• 3 citations
Publisher

Abstract

It is shown that broadband optical continua may be generated as light propagates through a coherently prepared medium. Stimulated Raman scattering is a parametric process responsible for the spectral broadening. Even though the generation of spectral components is limited by the dispersion of the medium, numerical estimates for realistic parameters show feasibility of generating coherent optical continua with total bandwidth of several hundred terahertz without implementation of any dispersion compensating technique. Finally, a technique for producing broadband coherent optical spectra and, thus, ultrashort pulses of radiation is proposed.

DOI
10.1103/physreva.64.063819

Related papers

Short pulse generation due to coherent population trapping

Roman L. Kolesov, Olga A. Kocharovskaya

An efficient broadband optical continua generation due to stimulated Raman scattering originated from relaxation processes from the excited electronic states is predicted. It is shown that, even when the populations of Raman levels are equal, Raman coherence can be efficiently excited due to coherent population trapping process (CPT). Scattering of the electromagnetic field due to the excited coherence gives rise to a comb of equally spaced spectral components of optical radiation. The generated spectrum can be compressed into a sequence of ultrashort pulses. Estimates for realistic parameters of the medium show that it is possible to produce a sequence of femtosecond and even subfemtosecond pulses with repetition rate several GHz.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•May 30, 2002•0 citations

'Tunnel' Locking Stimulated Raman Radiation Components in an Optical Resonator

V. N. Lugovoǐ, A. L. Dyshko

Stimulated Raman radiation is considered in an optical resonator excited by an external light beam. It is assumed that the resonator is filled with a dispersive (condensed) medium for a length of the medium (along the resonator axis) close to several ‘tunnel’ lengths. A Raman-active medium is assumed to fill part of the resonator length along the resonator axis. Numerical calculations are presented of tunnel locking stimulated Raman radiation components. The shape of light pulses is calculated, and the band of locking Stokes components is derived. The feasibility of generating a light pulse of duration 3 × 10-14 −4 × 10-15 s in a frequency region close to the point ∂2 n eff / ∂ω2 = 0, located usually in the infrared spectral region (n eff is the effective refractive index of the substance inside the resonator) is discussed. Also discussed is the feasibility of correcting the refractive index dispersion and generating femtosecond light pulses in the visible spectral region.

Optica Acta International Journal of Optics•May 1, 1983•5 citations

Possibility of generation of femtosecond pulses by stimulated Raman scattering in optical resonators

V. N. Lugovoǐ, V. N. Streltsov

An analysis is made of parametric excitation of anti-Stokes components of stimulated Raman scattering in an optical resonator filled with a medium whose refractive index is dispersion-free. The case of steady generation of the first Stokes component is considered. Expressions are obtained for the amplitudes of steady-state fluctuations of the anti-Stokes components in the case of a weak reaction of these components on the pump radiation and on the first Stokes component. Various cases of frequency dependences of the intrinsic resonator losses are considered. Conditions are found under which a large number of anti-Stokes components with similar intensities is excited so that the anti-Stokes radiation leaving the resonator is a periodic sequence of ultrashort (femtosecond) pulses with one pulse per period.

Soviet Journal of Quantum Electronics•Aug 31, 1976•2 citations

Coherent Generation of Short Terahertz Pulses in Doped Optical Crystals

Elena A. Kuznetsova, Yuri V. Rostovtsev, Nikolai G. Kalugin +3 more

Terahertz radiation has unique potential for applications to material diagnostics including semiconductors, chemical compounds, biomolecules and biotissues, imaging for medical and security applications, remote atmospheric sensing and monitoring, astronomy, etc. The search for efficient, high-power, inexpensive, portable and room temperature suitable methods of generation of THz radiation is one of the main topics in modern optoelectronics and photonics. Specifically, coherent solid-state compact efficient THz sources are desirable. Recently we suggested a new approach to the problem of generation of short coherent THz pulses in molecular gases taking advantage of the dramatic enhancement of a nonlinear response of a medium via quantum coherence. Stimulated Raman adiabatic passage (STIRAP) technique was proposed for preparation of maximal molecular coherence by two optical pump fields, which is further used to efficiently scatter off an IR probe beam and generate a Stokes THz field in a double Λ scheme. The central idea of the crystal-based technique is to generate THz radiation by resonantly inducing coherence at the corresponding transition by coherent optical fields. Electronic levels of the THz transition are coupled by a pair of optical fields to a common ground state forming a V scheme of energy levels. Coherence induced by the optical fields at the THz transition gives rise to polarization provided that the corresponding dipole moment is not zero, which will radiate out a THz pulse. We show that coherently driven molecular (such as methanol, H2F2, CH3Cl, etc.) and solid-state (ruby, alexandrite) media can potentially produce strong, controllable, short pulses of THz radiation. The pulses have energies ranging from hundreds pJ to J and time durations from several fs to ns at room temperature.

Frontiers in Optics•Jan 1, 2006•0 citations

Off-resonant preparation of a vibrational coherence for enhanced stimulated Raman scattering

Sarah Gundry, M. Anscombe, A M Abdulla +4 more

We present a detailed experimental investigation into the off-resonant preparation of a vibrational coherence for multiorder Raman generation. In particular, the importance of the balance between the conflicting requirements for generating a strong coherence and for adiabatic evolution of the system are examined. For the parameters accessible in our experiment, we find that the strongest frequency modulation occurs under conditions for which there is some nonadiabatic behavior, and the coherence is less than the peak value obtainable. We investigate the modulation of a narrowband probe pulse, and an ultrashort probe pulse, in the coherently prepared medium, and demonstrate efficient modulation of both probe pulses resulting in the generation of $360\phantom{\rule{0.3em}{0ex}}\mathrm{THz}$ bandwidth fields. This system therefore has an application in the field of subfemtosecond pulse generation.

Physical Review A•Sep 27, 2005•9 citations

Tunnel generation and locking stimulated Raman radiation components

V. N. Lugovoǐ

Stimulated Raman radiation is considered in a ring optical resonator. It is supposed that the resonator is partly filled with a condensed medium at the full length of the medium close to several tunnel lengths. A Raman-active medium and an optical waveguide are assumed to occupy a part of the condensed medium. The feasibility is shown of tunnel generation and synchronization of a great number of Stokes components of stimulated Raman radiation. Here, femtosecond light pulses are shown to be formed in a spacing adjacent to the Raman-active medium, the pulses being single over the periodT = 2\pi/\omega_{R}(ωRis the Raman frequency shift). Predicted and considered also are tunnel generation and locking of new light modes in an optical parametric oscillator. The effects are due to a correction for the dispersion of the full effective refractive index of the medium inside the resonator. Numerical calculations of the correction for a glass thin-film optical waveguide, quartz, and the Raman-active media CaCO3, C6H6, CS2inside the resonator are represented. Here, five or six Stokes components are shown to be generated and locked for CaCO3and C6H6, eight Stokes components for CS2. A similar numerical calculation is represented for the active medium LiNbO3in the corresponding optical parameteric oscillator. Here, new modes covering a frequency bandwidth of 5000 cm-1are shown to be feasible. Noted and discussed is also a higher-order correction for the effective refractive index dispersion making it feasible to broaden the frequency bandwidth for tunnel generation and locking.

IEEE Journal of Quantum Electronics•Aug 1, 1984•1 citation
It is shown that broadband optical continua may be generated as light propagates through a coherently prepared medium. Stimulated Raman scattering is a parametric process responsible for the spectral broadening. Even though the generation of spectral components is limited by the dispersion of the medium, numerical estimates for realistic parameters show feasibility of generating coherent optical continua with total bandwidth of several hundred terahertz without implementation of any dispersion compensating technique. Finally, a technique for producing broadband coherent optical spectra and, thus, ultrashort pulses of radiation is proposed.
An efficient broadband optical continua generation due to stimulated Raman scattering originated from relaxation processes from the excited electronic states is predicted. It is shown that, even when the populations of Raman levels are equal, Raman coherence can be efficiently excited due to coherent population trapping process (CPT). Scattering of the electromagnetic field due to the excited coherence gives rise to a comb of equally spaced spectral components of optical radiation. The generated spectrum can be compressed into a sequence of ultrashort pulses. Estimates for realistic parameters of the medium show that it is possible to produce a sequence of femtosecond and even subfemtosecond pulses with repetition rate several GHz.
Stimulated Raman radiation is considered in an optical resonator excited by an external light beam. It is assumed that the resonator is filled with a dispersive (condensed) medium for a length of the medium (along the resonator axis) close to several ‘tunnel’ lengths. A Raman-active medium is assumed to fill part of the resonator length along the resonator axis. Numerical calculations are presented of tunnel locking stimulated Raman radiation components. The shape of light pulses is calculated, and the band of locking Stokes components is derived. The feasibility of generating a light pulse of duration 3 × 10-14 −4 × 10-15 s in a frequency region close to the point ∂2 n eff / ∂ω2 = 0, located usually in the infrared spectral region (n eff is the effective refractive index of the substance inside the resonator) is discussed. Also discussed is the feasibility of correcting the refractive index dispersion and generating femtosecond light pulses in the visible spectral region.
An analysis is made of parametric excitation of anti-Stokes components of stimulated Raman scattering in an optical resonator filled with a medium whose refractive index is dispersion-free. The case of steady generation of the first Stokes component is considered. Expressions are obtained for the amplitudes of steady-state fluctuations of the anti-Stokes components in the case of a weak reaction of these components on the pump radiation and on the first Stokes component. Various cases of frequency dependences of the intrinsic resonator losses are considered. Conditions are found under which a large number of anti-Stokes components with similar intensities is excited so that the anti-Stokes radiation leaving the resonator is a periodic sequence of ultrashort (femtosecond) pulses with one pulse per period.
Terahertz radiation has unique potential for applications to material diagnostics including semiconductors, chemical compounds, biomolecules and biotissues, imaging for medical and security applications, remote atmospheric sensing and monitoring, astronomy, etc. The search for efficient, high-power, inexpensive, portable and room temperature suitable methods of generation of THz radiation is one of the main topics in modern optoelectronics and photonics. Specifically, coherent solid-state compact efficient THz sources are desirable. Recently we suggested a new approach to the problem of generation of short coherent THz pulses in molecular gases taking advantage of the dramatic enhancement of a nonlinear response of a medium via quantum coherence. Stimulated Raman adiabatic passage (STIRAP) technique was proposed for preparation of maximal molecular coherence by two optical pump fields, which is further used to efficiently scatter off an IR probe beam and generate a Stokes THz field in a double Λ scheme. The central idea of the crystal-based technique is to generate THz radiation by resonantly inducing coherence at the corresponding transition by coherent optical fields. Electronic levels of the THz transition are coupled by a pair of optical fields to a common ground state forming a V scheme of energy levels. Coherence induced by the optical fields at the THz transition gives rise to polarization provided that the corresponding dipole moment is not zero, which will radiate out a THz pulse. We show that coherently driven molecular (such as methanol, H2F2, CH3Cl, etc.) and solid-state (ruby, alexandrite) media can potentially produce strong, controllable, short pulses of THz radiation. The pulses have energies ranging from hundreds pJ to J and time durations from several fs to ns at room temperature.
We present a detailed experimental investigation into the off-resonant preparation of a vibrational coherence for multiorder Raman generation. In particular, the importance of the balance between the conflicting requirements for generating a strong coherence and for adiabatic evolution of the system are examined. For the parameters accessible in our experiment, we find that the strongest frequency modulation occurs under conditions for which there is some nonadiabatic behavior, and the coherence is less than the peak value obtainable. We investigate the modulation of a narrowband probe pulse, and an ultrashort probe pulse, in the coherently prepared medium, and demonstrate efficient modulation of both probe pulses resulting in the generation of 360THz360\phantom{\rule{0.3em}{0ex}}\mathrm{THz}360THz bandwidth fields. This system therefore has an application in the field of subfemtosecond pulse generation.
Stimulated Raman radiation is considered in a ring optical resonator. It is supposed that the resonator is partly filled with a condensed medium at the full length of the medium close to several tunnel lengths. A Raman-active medium and an optical waveguide are assumed to occupy a part of the condensed medium. The feasibility is shown of tunnel generation and synchronization of a great number of Stokes components of stimulated Raman radiation. Here, femtosecond light pulses are shown to be formed in a spacing adjacent to the Raman-active medium, the pulses being single over the periodT = 2\pi/\omega_{R}(ωRis the Raman frequency shift). Predicted and considered also are tunnel generation and locking of new light modes in an optical parametric oscillator. The effects are due to a correction for the dispersion of the full effective refractive index of the medium inside the resonator. Numerical calculations of the correction for a glass thin-film optical waveguide, quartz, and the Raman-active media CaCO3, C6H6, CS2inside the resonator are represented. Here, five or six Stokes components are shown to be generated and locked for CaCO3and C6H6, eight Stokes components for CS2. A similar numerical calculation is represented for the active medium LiNbO3in the corresponding optical parameteric oscillator. Here, new modes covering a frequency bandwidth of 5000 cm-1are shown to be feasible. Noted and discussed is also a higher-order correction for the effective refractive index dispersion making it feasible to broaden the frequency bandwidth for tunnel generation and locking.