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

Broadband coherent light generation in diamond driven by femtosecond pulses

Miaochan Zhi, Xi Wang, Alexei V. Sokolov

Published Jul 29, 2008• 59 citations
Publisher

Abstract

We demonstrate broadband light generation in diamond pumped by two-color femtosecond laser pulses. We find that phase matching plays a critical role in the output angle and frequency of the generated sidebands. When a third femtosecond probe pulse is applied to the crystal in the boxed Coherent anti-Stokes Raman Scattering geometry, a two-dimensional array of multi-color beams is generated through the Raman, four-wave mixing, and six-wave-mixing processes. We test the mutual coherence between the generated sidebands. Such coherence, maintained over the broad spectrum, opens possibilities for synthesis of subfemtosecond light waveforms.

DOI
10.1364/oe.16.012139

Related papers

Efficient Broadband Raman Generation in Diamond Driven by multi-frequency femtosecond pulses

Xi Wang, Miaochan Zhi, Alexei V. Sokolov

We demonstrate efficient generation of multiple spatially-separated and frequency-shifted anti-Stokes and Stokes sidebands due to strong near-resonant excitation of Raman transition by crossing two- or three-color femtosecond laser pulses into diamond.

Advanced Solid-State Photonics (TOPS)•Jan 1, 2009•0 citations

Broadband generation in a Raman crystal driven by a pair of time-delayed linearly chirped pulses

Miaochan Zhi, Alexei V. Sokolov

A pair of time-delayed linearly chirped pulses with sub-picosecond duration is used to selectively excite Raman transitions in a lead tungstate crystal. Significant molecular coherence leads to generation of up to 40 anti-Stokes and 5 Stokes sidebands. High conversion efficiency (from the two pump beams to the sidebands) is measured. The broadband generation with chirped pulses whose duration is comparable to the Raman coherence lifetime is considerably more efficient, when compared to the case of excitation by two-color femtosecond pulses. In the future, mutual coherence among the generated sidebands may allow ultrashort pulse synthesis.

New Journal of Physics•Feb 29, 2008•43 citations

Generation of subfemtosecond pulse by nonadiabatic Raman excitation

Jian Wu, Kun Wu, Heping Zeng

Subfemtosecond pulses can be generated in a Raman generator by using electromagnetically induced transparency if ultrabroad Raman sidebands are generated and then propagate in such a way that the generated sidebands at higher frequencies are temporally advanced with regard to those at lower frequencies. However, it was recently demonstrated by experiments [1] that above-resonance Raman excitations ensured the establishment of anti-phased Raman coherence for pulse compression but only very limited number of Raman sidebands could be generated due to Raman self-defocusing [2], while broadband sidebands could be generated under below-resonance Raman excitations, which supported no pulse compression in the same Raman media. In order to establish anti-phased Raman coherence and simultaneously overcome Raman self-defocusing to benefit efficient generation of broadband sidebands, we suggest in this report a new technique to generate sub-fs pulse train in a Raman generator driven by three sufficiently intense single-mode laser beams whose carrier frequencies are tuned off the Raman resonance with two different two-photon detunings. The Raman interaction establishes a molecular modulation through nonadibatic processes. The simulation on the basis of the fundamental rotational Raman transitions in H2 shows that sub-fs pulse can be generated by above-resonance or below-resonance Raman excitations, or even Raman excitations with opposite detunings, as is shown in Fig.1. This opens a new way for experiments to observe enhanced generation of broadband Raman sidebands, together with compression of the phase-locked Raman sidebands into sub-fs pulse trains in the same Raman media

Frontiers in Optics•Jan 1, 2003•0 citations

Pulse-shaper-assisted phase control of a coherent broadband spectrum of Raman sidebands

M. Zhi, Kai Wang, Xia Hua +1 more

We report pulse-shaper-assisted phase control of a broad spectrum, aiming to synthesize nonsinusoidal waveforms. We first generate multiple-order coherent Raman sidebands by focusing two laser beams into a piece of diamond. Then we combine five sidebands into a single beam by using a prism. Our setup allows for both coarse, manual phase adjustments and fine tuning of the spectral phases. A flat spectral phase across these five frequency-separated sub-bands is achieved, which implies generation of two to three optical-cycle pulses.

Optics Letters•Oct 6, 2011•20 citations

Ultra-broadband frequency generation in a cavity confined Raman medium

CS Rose

Throughout the past few decades, science has progressed towards the ability to probe many extremely fast processes and a large amount of research has been aimed at the area of few-femtosecond pulse generation. This thesis describes the generation of coherent broadband radiation through two-colour pumping of molecular hydrogen confined to a unidirectional ring cavity, and the subsequent synthesis of high peak power and few-femtosecond pulses. A set of normalised semi-classical field equations are derived in Bloch form describing the process of ultra-broadband multi-frequency Raman generation or UMRG, and a 3-wave gain suppression analysis is derived from a subset of the plane wave UMRG field equations which describes gain suppression within the ring cavity in terms of both medium and cavity parameters. The gain suppression analysis is further generalised to include finite levels of linear two-photon frequency detuning of the pump beams. Simulations of the plane wave ultra-broadband multi-frequency Raman (UMRG) equations show that a broad frequency spectrum of mutually coherent sideband can be generated. The inverse Fourier transform of spectra generated in this way yields a train of high power near Fourier limited pulses in the time domain which can range from a few-femtoseconds in duration to tens of attoseconds with repetition rates equal to the Raman transition frequency. Pulses synthesised in this way are limited only by the level of medium dispersion, the reflection bandwidth of the chosen coupling mirror and the chosen Raman medium. Simulations of the transverse UMRG equations within the ring cavity geometry have shown ring cavity enhanced UMRG to be resilient to transverse effects such as finite beam width, beam diffraction and the transverse beam separation of the applied pump beams.

•Sep 30, 2013•0 citations

Generation and control of femtosecond pulses by molecular modulation

Alexei V. Sokolov, Miro Y. Shverdin, D. R. Walker +4 more

We have demonstrated that coherent molecular modulation can result in the collinear generation of mutually-coherent spectral sidebands that extend in frequency from the infrared to the far ultraviolet. Our technique is based on adiabatic preparation of a highly coherent molecular superposition-state, which is achieved by using narrow-linewidth lasers slightly detuned from a Raman resonance. The phases of the resultant Stokes and anti-Stokes sidebands are adjusted in order to synthesize desired single-cycle pulse trains at the target. In this article we review recent improvements and developments in this area, including: techniques for increasing the number of generated sidebands; synchronization of the pulse trains with the molecular motion in the given molecular system; laser self-focusing and spatial soliton formation due to the coherent interaction of light with oscillating molecules. In the future, this Raman source may produce sub-cycle optical pulses, and allow synthesis of waveforms where the electric field is a predetermined function of time, not limited to a quasi-sinusoidal oscillation.

Journal of Modern Optics•Jan 20, 2005•67 citations
We demonstrate broadband light generation in diamond pumped by two-color femtosecond laser pulses. We find that phase matching plays a critical role in the output angle and frequency of the generated sidebands. When a third femtosecond probe pulse is applied to the crystal in the boxed Coherent anti-Stokes Raman Scattering geometry, a two-dimensional array of multi-color beams is generated through the Raman, four-wave mixing, and six-wave-mixing processes. We test the mutual coherence between the generated sidebands. Such coherence, maintained over the broad spectrum, opens possibilities for synthesis of subfemtosecond light waveforms.
A pair of time-delayed linearly chirped pulses with sub-picosecond duration is used to selectively excite Raman transitions in a lead tungstate crystal. Significant molecular coherence leads to generation of up to 40 anti-Stokes and 5 Stokes sidebands. High conversion efficiency (from the two pump beams to the sidebands) is measured. The broadband generation with chirped pulses whose duration is comparable to the Raman coherence lifetime is considerably more efficient, when compared to the case of excitation by two-color femtosecond pulses. In the future, mutual coherence among the generated sidebands may allow ultrashort pulse synthesis.
Subfemtosecond pulses can be generated in a Raman generator by using electromagnetically induced transparency if ultrabroad Raman sidebands are generated and then propagate in such a way that the generated sidebands at higher frequencies are temporally advanced with regard to those at lower frequencies. However, it was recently demonstrated by experiments [1] that above-resonance Raman excitations ensured the establishment of anti-phased Raman coherence for pulse compression but only very limited number of Raman sidebands could be generated due to Raman self-defocusing [2], while broadband sidebands could be generated under below-resonance Raman excitations, which supported no pulse compression in the same Raman media. In order to establish anti-phased Raman coherence and simultaneously overcome Raman self-defocusing to benefit efficient generation of broadband sidebands, we suggest in this report a new technique to generate sub-fs pulse train in a Raman generator driven by three sufficiently intense single-mode laser beams whose carrier frequencies are tuned off the Raman resonance with two different two-photon detunings. The Raman interaction establishes a molecular modulation through nonadibatic processes. The simulation on the basis of the fundamental rotational Raman transitions in H2 shows that sub-fs pulse can be generated by above-resonance or below-resonance Raman excitations, or even Raman excitations with opposite detunings, as is shown in Fig.1. This opens a new way for experiments to observe enhanced generation of broadband Raman sidebands, together with compression of the phase-locked Raman sidebands into sub-fs pulse trains in the same Raman media
We report pulse-shaper-assisted phase control of a broad spectrum, aiming to synthesize nonsinusoidal waveforms. We first generate multiple-order coherent Raman sidebands by focusing two laser beams into a piece of diamond. Then we combine five sidebands into a single beam by using a prism. Our setup allows for both coarse, manual phase adjustments and fine tuning of the spectral phases. A flat spectral phase across these five frequency-separated sub-bands is achieved, which implies generation of two to three optical-cycle pulses.
Throughout the past few decades, science has progressed towards the ability to probe many extremely fast processes and a large amount of research has been aimed at the area of few-femtosecond pulse generation. This thesis describes the generation of coherent broadband radiation through two-colour pumping of molecular hydrogen confined to a unidirectional ring cavity, and the subsequent synthesis of high peak power and few-femtosecond pulses. A set of normalised semi-classical field equations are derived in Bloch form describing the process of ultra-broadband multi-frequency Raman generation or UMRG, and a 3-wave gain suppression analysis is derived from a subset of the plane wave UMRG field equations which describes gain suppression within the ring cavity in terms of both medium and cavity parameters. The gain suppression analysis is further generalised to include finite levels of linear two-photon frequency detuning of the pump beams. Simulations of the plane wave ultra-broadband multi-frequency Raman (UMRG) equations show that a broad frequency spectrum of mutually coherent sideband can be generated. The inverse Fourier transform of spectra generated in this way yields a train of high power near Fourier limited pulses in the time domain which can range from a few-femtoseconds in duration to tens of attoseconds with repetition rates equal to the Raman transition frequency. Pulses synthesised in this way are limited only by the level of medium dispersion, the reflection bandwidth of the chosen coupling mirror and the chosen Raman medium. Simulations of the transverse UMRG equations within the ring cavity geometry have shown ring cavity enhanced UMRG to be resilient to transverse effects such as finite beam width, beam diffraction and the transverse beam separation of the applied pump beams.
We have demonstrated that coherent molecular modulation can result in the collinear generation of mutually-coherent spectral sidebands that extend in frequency from the infrared to the far ultraviolet. Our technique is based on adiabatic preparation of a highly coherent molecular superposition-state, which is achieved by using narrow-linewidth lasers slightly detuned from a Raman resonance. The phases of the resultant Stokes and anti-Stokes sidebands are adjusted in order to synthesize desired single-cycle pulse trains at the target. In this article we review recent improvements and developments in this area, including: techniques for increasing the number of generated sidebands; synchronization of the pulse trains with the molecular motion in the given molecular system; laser self-focusing and spatial soliton formation due to the coherent interaction of light with oscillating molecules. In the future, this Raman source may produce sub-cycle optical pulses, and allow synthesis of waveforms where the electric field is a predetermined function of time, not limited to a quasi-sinusoidal oscillation.