# 0.24 TW Ultrabroadband, CEP-stable Multipass Ti:Sa Amplifier

## TL;DR

This paper presents a high-energy, ultrabroadband, CEP-stable multipass Ti:sapphire amplifier capable of delivering sub-13 fs pulses with active CEP stabilization, advancing ultrafast laser technology.

## Contribution

It introduces a single-stage multipass Ti:sapphire amplifier with active CEP stabilization and ultrabroadband spectrum, achieving high pulse energy and stability in a compact setup.

## Key findings

- Sub-13 fs pulse duration achieved
- CEP noise <150 mrad over 75 hours
- Ultrabroadband spectrum with >130 nm bandwidth

## Abstract

We demonstrate a single-stage, multipass Ti:sapphire amplifier capable of delivering sub-13 fs, 3.2 mJ pulses at 1 kHz repetition rate. Gaussian filters are used to suppress the gain-narrowing effect, thereby enabling the achievement of an ultrabroadband flat-top spectrum with a FWHM > 130 nm. The carrier-envelope phase (CEP) of the output pulses is actively stabilized via the feed-forward scheme (for the oscillator) and a fast 1 kHz f-to-2f interferometer, which corrects the amplifier-induced CEP drift. The single-shot 75 h CEP measurement yielded rms noise of <150 mrad.