Abstract
The shortest to date optical pulse length of 6 fs [1] was achieved by using pulse compression technique. Further shortening could be attained by using a Fourier synthesizer [2] of separate lasers synchronized by nonlinear phase-locking [3]. Here, we propose a new approach [4] based on multi-frequency cascade Raman stimulated scattering (CSRS) whose components are mode-locked within 2π soliton reminiscent to the self-induced transparency solitons [5], We show that Raman active materials can support solitons consisting of pump laser wave with the frequency ωL and many cascade-excited Stocks and anti-Stocks component with their frequencies ωj = ωL + jω0, j =±1, +2, +3…, mode-locked to each other through a fast "fullswing" 2π-nutation of population at the Raman transition with the frequency ω0 ≪ ωL. Similarly to "bright-bright" 2π-solitons in CSRS with two [6] and three [7] components, these solitons have a new, very simple, Lorentzian intensity profile. Due to the engagement of many mode-locked components, however, their total EM field in the time domain consists of the train of ultra-short pulses (separated by the interval 2π/ω0) with their length being of the same order of magnitude or even shorter than the pump cycle, 2π/ωL. The major feature of the proposed effect is that all the frequency components of the new soliton are so called bright solitons (in contrast to the well known bright+dark soliton combination in SRS [8]) locked to each other and propagating with the same group velocity. The high-order CSRS required to observe the proposed effect, was first observed experimentally in [9] and later in many other experiments, with the total number of components up to ~10-15. The lock-in of all these components into "all-bright-SRS" 2π soliton, however, has never been observed in experiment; its feasibility and resulting effects are discussed here.
© 1995 Optical Society of America
PDF ArticleMore Like This
A. E. Kaplan
WC14 High Resolution Fourier Transform Spectroscopy (FTS) 1994
A. E. Kaplan and P. L. Shkolnikov
QMD5 Quantum Electronics and Laser Science Conference (CLEO:FS) 1995
A. E. Kaplan and P. L. Shkolnikov
ThE28 Applications of High Field and Short Wavelength Sources (HFSW) 1997