High harmonic phase in molecular nitrogen

Journal Article · Sat Oct 17 00:00:00 EDT 2009 · Submitted to Physical Review A

DOI:https://doi.org/10.1103/PhysRevA.80.033412· OSTI ID:968523

McFarland, Brian K

Electronic structure in atoms and molecules modulates the amplitude and phase of high harmonic generation (HHG). We report measurements of the high harmonic spectral amplitude and phase in N{sub 2}. The phase is measured interferometrically by beating the N{sub 2} harmonics with those of an Ar reference oscillator in a gas mixture. A rapid phase shift of 0.2{pi} is observed in the vicinity of the HHG spectral minimum, where a shift of {pi} had been presumed [J. Itatani et al., Nature 432, 867 (2004)]. We compare the phase measurements to a simulation of the HHG recombination step in N{sub 2} that is based on a simple interference model. The results of the simulation suggest that modifications beyond the simple interference model are needed to explain HHG spectra in molecules.

• Research Organization: Stanford Linear Accelerator Center (SLAC)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC02-76SF00515
• OSTI ID: 968523
• Report Number(s): SLAC-PUB-13761
• Journal Information: Submitted to Physical Review A, Journal Name: Submitted to Physical Review A
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
ELECTRONIC STRUCTURE
HARMONIC GENERATION
MATHEMATICAL MODELS
NITROGEN
OPTICS
PHYS
OSCILLATORS
PHASE SHIFT
RECOMBINATION
SPECTRA