Kevin F. Lee

Two-pulse alignment of molecules

Field-free alignment of gas-phase molecules can be achieved by creating rotational wavepackets with a short laser pulse. We demonstrate that the degree of alignment can be improved by illuminating the molecules with a second laser pulse at a specific time during the evolution of the original rotational wavepacket.

Surpassing the path-limited resolution of Fourier-transform spectrometry with frequency combs

We overcome the resolution limit of Fourier-transform spectrometry and measure instrumental line-shape-free broadband molecular spectra with lines narrower than the optical path-limited resolution. ...

Fourier transform and Vernier spectroscopy using an optical frequency comb at 3–5.4 μm

We present a versatile mid-infrared frequency comb spectroscopy system based on a doubly resonant optical parametric oscillator tunable in the 3-5.4 μm range and two detection methods: a Fourier transform spectrometer (FTS) and a continuous-filtering Vernier spectrometer (CF-VS). Using the FTS with a multipass cell, we measure high precision broadband absorption spectra of CH4 at 3.3 μm and NO at 5.25 μm, the latter for the first time with comb spectroscopy, and we detect atmospheric species (CH4, CO, CO2, and H2O) in air in the signal and idler ranges. Multiline fitting yields minimum detectable concentrations of 10-20  ppb Hz-1/2 for CH4, NO, and CO. For the first time in the mid-infrared, we perform CF-VS using an enhancement cavity, a grating, and a single detector, and we measure the absorption spectrum of CH4 and H2O in ambient air at ∼3.3  μm, reaching a 40 ppb concentration detection limit for CH4 in 2 ms.We present a versatile mid-infrared frequency comb spectroscopy system based on a doubly resonant optical parametric oscillator tunable in the 3-5.4 {\mu}m range and two detection methods, a Fourier transform spectrometer (FTS) and a Vernier spectrometer. Using the FTS with a multipass cell we measure high-precision broadband absorption spectra of CH

Midinfrared frequency comb from self-stable degenerate GaAs optical parametric oscillator

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Laser Coulomb explosion imaging for probing ultra-fast molecular dynamics

and NO at ~3.3 {\mu}m and ~5.2 {\mu}m, respectively, and of atmospheric species (CH

Coincidence imaging of polyatomic molecules via laser-induced Coulomb explosion

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Measured field-free alignment of deuterium by few-cycle pulses

, CO, CO

Harmonic generation in solids with direct fiber laser pumping

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Three-photon absorption in optical parametric oscillators based on OP-GaAs

and H

Self-referenced, accurate and sensitive optical frequency comb spectroscopy with a virtually imaged phased array spectrometer

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