We have analyzed the temporal characteristics of amplified spontaneous emission (ASE) in femtosecond terawatt Ti:sapphire lasers by using a simple method based on fast photodiodes. Instead of measuring ASE directly with fast photodiodes, we created a narrow gap in the spectrum of seed pulses and, after amplification, detected the pure ASE signal through the gap by using a fast photodiode covered with a bandpass filter with high transmission at the gap. Because the detected ASE signal was completely separated from amplified main pulses, preceding and even trailing ASEs could be characterized quantitatively in a single-shot measurement. We believe that our method is a good alternative or a complement to conventional methods for ASE measurements.
© 2007 Optical Society of America
Lasers and Laser Optics
Original Manuscript: June 5, 2007
Revised Manuscript: August 9, 2007
Manuscript Accepted: August 9, 2007
Published: September 21, 2007
Yong-Ho Cha, Yong-Woo Lee, Sung Mo Nam, Jae Min Han, Yong Joo Rhee, Byung Duk Yoo, Byoung Chul Lee, and Young Uk Jeong, "Simple method for the temporal characterization of amplified spontaneous emission in femtosecond terawatt Ti:sapphire lasers," Appl. Opt. 46, 6854-6858 (2007)