Ultrafast-Laser Stabilization with Application to Pulse Amplification by Use of Passive Optical Cavities

Abstract

Stabilization and control of the femtosecond laser is becoming increasingly important as novel applications utilizing the femtosecond comb are developed that require greater levels of precision. Improved stability is beneficial for both” “frequency domain” applications, where the relative quadratic phase between comb components, or “chirp”, is unimportant (e.g. optical frequency metrology), as well as “time domain” applications where the pulse shape and/or duration is vital, such as in nonlinear optical interactions [1]. For both types of applications, minimizing jitter in the pulse train and noise in the carrier-envelope (CE) phase is often critical to achieve the desired level of precision. The stabilization of mode-locked femtosecond lasers has played a key role in recent advances in optical frequency measurement [2, 3], carrier-envelope phase stabilization [4,5], all-optical atomic clocks [6, 7] and coherent pulse synthesis [8]. Proper stabilization of ultrafast lasers can allow efficient coupling and temporary storage of ultrashort light pulses inside high finesse cavities [9]. This enables exciting possibilities for advancing external enhancement-cavity based techniques for short pulses, such as nonlinear frequency conversion [10], intracavity spectroscopy [11], and coherent pulse “amplification” [12,13] to name a few. A highly stable cavity may even itself serve as a frequency and phase reference for the pulse train [14]. This provides strong motivation to further improve tools for ultrafast laser control. Here we describe efforts in both active stabilization of ultrafast lasers and in storing these pulses in high finesse passive cavities. Results are given for pulse amplification when the single intracavity pulse is switched out with a Brag cell acting as a cavity dumper.