Slow amplitude modulation in the pulse train of a self-mode-locked Ti:sapphire laser

Journal Article · Fri Oct 01 04:00:00 EDT 1993 · IEEE Journal of Quantum Electronics (Institute of Electrical and Electronics Engineers); (United States)

OSTI ID:5354220

Liu, Yan Ming; Prucnal, P R ^[1]

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1. Princeton Univ., NJ (United States). Advanced Technology Center for Photonics and Optoelectronic Materials

Periodic pulse-train amplitude modulations have been observed in a Kerr-lens self-mode-locked Ti:sapphire laser when the size of an intracavity slit is reduced below its optimal value for stable model locking. These transient processes are dominated by 100--500 kHz periodic pulse-energy modulations and are inherent to the Kerr-lens mode-locking mechanism based on the intensity dependent transverse-beam profile of the laser and the long gain relaxation lifetime (3.2 [mu]s) of the Ti:sapphire rod. They observe that when the slit width is decreased from 2 mm to 1.4 mm the modulation period increases from 2 [mu]s to 10 [mu]s and amplitude modulation deepens to almost 100%. An explanation similar to repetitive self-Q-switching and undamped relaxation oscillation is presented, which is consistent with the experimental results. A large low-frequency timing jitter on the order of submicroseconds, associated with the periodic pulse-train modulations, is also observed. The timing jitter is analyzed by incorporating the pulse-energy modulation into the phase variation through the Kerr effect and consistent results are obtained. They have determined the cavity parameters to control these detrimental processes for stable mode-locked output. The observation of the amplitude modulation further confirms the Kerr-lens self-focusing model of self-model locking in Ti:sapphire lasers.

• OSTI ID: 5354220
• Journal Information: IEEE Journal of Quantum Electronics (Institute of Electrical and Electronics Engineers); (United States), Journal Name: IEEE Journal of Quantum Electronics (Institute of Electrical and Electronics Engineers); (United States) Vol. 29:10; ISSN 0018-9197; ISSN IEJQA7
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
426002* -- Engineering-- Lasers & Masers-- (1990-)
APERTURES
DYNAMICS
ELECTROMAGNETIC PULSES
ELECTROMAGNETIC RADIATION
LASER CAVITIES
LASERS
MECHANICS
MODE LOCKING
OPENINGS
PULSES
QUASI PARTICLES
RADIATIONS
SOLID STATE LASERS
SOLITONS