Active/passive mode-locked laser oscillator

US4019156A · kind A · utility

Assignee

• The United States of America as represented by the United States Energy Research and Development Administration · US

Inventors

• William D. Fountain · Fremont, US
• Bertram C. Johnson · Sunnyvale, US

Key dates

• Filing date: Dec 2, 1975
• Grant date: Apr 19, 1977
• Expiry date: Dec 2, 1995

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01S3/127
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

A Q-switched/mode-locked Nd:YAG laser oscillator employing simultaneous active (electro-optic) and passive (saturable absorber) loss modulation within the optical cavity is described. This "dual modulation" oscillator can produce transform-limited pulses of duration ranging from about 30 psec to about 5 nsec with greatly improved stability compared to other mode-locked systems. The pulses produced by this system lack intrapulse frequency or amplitude modulation, and hence are idealy suited for amplification to high energies and for other applications where well-defined pulses are required. Also, the pulses of this system have excellent interpulse characteristics, wherein the optical noise between the individual pulses of the pulse train has a power level well below the power of the peak pulse of the train.