Abstract
A noncollinear optical parametric amplifier (NOPA) can produce few-cycle femtosecond laser pulses that are ideally suited for time-resolved optical spectroscopy measurements. However, the nonlinear-optical process giving rise to ultrabroadband pulses is susceptible to spatiotemporal dispersion problems. Here, we detail refinements, including chirped-pulse amplification (CPA) and pulse-front matching (PFM), that minimize spatiotemporal dispersion and thereby improve the properties of ultrabroadband pulses produced by a NOPA. The description includes a rationale behind the choices of optical and optomechanical components, as well as assessment protocols. We demonstrate these techniques using a 1 kHz, second-harmonic Ti:sapphire pump configuration, which produces ∼5-fs duration pulses that span from about 500 to 800 nm with a bandwidth of about 200 THz. To demonstrate the utility of the CPA-PFM-NOPA, we measure vibrational quantum beats in the transient–absorption spectrum of methylene blue, a dye molecule that serves as a reference standard.
Original language | American English |
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Article number | 033002 |
Journal | Review of Scientific Instruments |
Volume | 95 |
Issue number | 3 |
DOIs | |
State | Published - 1 Mar 2024 |
Keywords
- chirped pulse amplification
- femtosecond lasers
- methylene blue
- nonlinear optical processes
- optical parametric amplifiers
- supercontinuum generation
EGS Disciplines
- Materials Science and Engineering