Generation of high-quality petawatt pulses
- Michigan Univ., Ann Arbor, MI (United States)
CPA sources need a front-end capable of generating very short seed pulses. To meet this requirement, present CPA sources rely on actively modelocked solid-state oscillators used in conjunction with non-linear fiber stages. This approach generates pulses with a residual frequency chirp, resulting in a limited peak-to-background intensity contrast ratio. The availability of an oscillator capable of producing directly (i.e. without fiber stage) picosecond or sub-picosecond pulses would significantly improve the quality of CPA sources. We have pursued different approaches to replace the standard modelocked oscillator front-end. In an initial phase, we investigated the possible use of Additive Pulse Modelocking (APM) color-center lasers as oscillators for CPA Nd:glass sources. Lately we have developed a Ti:Sapphire modelocked oscillator operating in the one-micron range. In order to generate pulses with very high peak to background contrast ratio, we have built a non-linear coupled-cavity oscillator generating 200-fs pulses. This color-center laser operates in the 1.5--1.6 micron range. A diagram of the oscillator is shown in Fig. 1. The laser is pumped with a modelocked Nd:YAG source. Both KCl and NaCl crystals were tested as gain media. NaCl was found to have a larger tuning range and to generate a higher average power (up to 150 mW). When synchronously mode-locked, the color-center generates pulses in the 10--20 ps range. Once interferometrically coupled to non-linear external-cavity, this oscillator produces very short pulses (85 to 260 fs). This oscillator was first operated with a 2 mm birefringent plate. 85 fs, near transform-limited pulses were generated at 1.54 micron. As the laser was tuned to longer wavelength, the pulse duration increased, as well as the bandwidth-duration product. With a 4 mm birefringent plate, 125 fs, transform-limited pulses were generated over the full tuning range.
- Research Organization:
- Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Univ. of Michigan, Ann Arbor, MI (United States)
- Sponsoring Organization:
- USDOE; USDOE, Washington, DC (United States)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 6061222
- Report Number(s):
- UCRL-CR-108460; ON: DE92003965
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
36 MATERIALS SCIENCE
SOLID STATE LASERS
TIME RESOLUTION
DESIGN
OSCILLATORS
POTASSIUM CHLORIDES
PROGRESS REPORT
PULSE AMPLIFIERS
SAPPHIRE
SODIUM CHLORIDES
TITANIUM
ALKALI METAL COMPOUNDS
AMPLIFIERS
CHLORIDES
CHLORINE COMPOUNDS
CORUNDUM
DOCUMENT TYPES
ELECTRONIC EQUIPMENT
ELEMENTS
EQUIPMENT
HALIDES
HALOGEN COMPOUNDS
LASERS
METALS
MINERALS
OXIDE MINERALS
POTASSIUM COMPOUNDS
RESOLUTION
SODIUM COMPOUNDS
TIMING PROPERTIES
TRANSITION ELEMENTS
426002* - Engineering- Lasers & Masers- (1990-)
360606 - Other Materials- Physical Properties- (1992-)