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We demonstrate spectral broadening and compression of amplified pulses from a titanium sapphire laser system using an argon-filled stretched, hollow-core fiber and an acousto-optic modulator based pulse-shaper. We characterize the pulses using pulse-shaper assisted collinear frequency resolved optical gating, pulse-shaper assisted D-scans, and D-scans using a variable path length water cell. The different compression and characterization approaches consistently compress the pulses down to < 6 fs, less than ∼1 fs from the transform limit. We discuss prospects for pulse shape spectroscopy with these broadband pulses, given our control over the spectral amplitude and phase.
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Deep learning of ultrafast pulses with a multimode fiber
Characterizing ultrashort optical pulses has always been a critical but difficult task, which has a broad range of applications. We propose and demonstrate a self-referenced method of characterizing ultrafast pulses with a multimode fiber. The linear and nonlinear speckle patterns formed at the distal end of a multimode fiber are used to recover the spectral amplitude and phase of an unknown pulse. We deploy a deep learning algorithm for phase recovery. The diversity of spatial and spectral modes in a multimode fiber removes any ambiguity in the sign of the recovered spectral phase. Our technique allows for single-shot pulse characterization in a simple experimental setup. This work reveals the potential of multimode fibers as a versatile and multi-functional platform for optical sensing.
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- Award ID(s):
- 1809099
- PAR ID:
- 10594415
- Publisher / Repository:
- American Institute of Physics
- Date Published:
- Journal Name:
- APL Photonics
- Volume:
- 5
- Issue:
- 9
- ISSN:
- 2378-0967
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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