Ultrafast laser-triggered emission from hafnium carbide tips

Autor(en)

Catherine Kealhofer, Seth M. Foreman, Stefan Gerlich, Mark A. Kasevich

Abstrakt

Electron emission from hafnium carbide (HfC) field emission tips induced by a sub-10-fs, 150-MHz repetition rate Ti:sapphire laser is studied. Two-photon emission is observed at low power with a moderate electric bias field applied to the tips. As the bias field and/or laser power is increased, the average current becomes dominated by thermally enhanced field emission due to laser heating: both the low thermal conductivity of HfC and the laser's high repetition rate can lead to a temperature rise of several hundred Kelvin at the tip apex. The contribution of current from a thermal transient at times shorter than the electron-phonon coupling time is considered in the context of the two-temperature model (TTM). Under the conditions of this experiment, the integrated current from the thermal transient is shown to be negligible in comparison with the two-photon emission. A finite element model of the laser heating and thermal conduction supports these conclusions and is also used to compare the nature of thermal effects in HfC, tungsten, and gold tips.

Organisation(en)

Quantenoptik, Quantennanophysik und Quanteninformation

Externe Organisation(en)

Stanford University

Journal

Physical Review B

Band

86

Anzahl der Seiten

11

ISSN

1098-0121

DOI

https://doi.org/10.1103/PhysRevB.86.035405

Publikationsdatum

2012

Peer-reviewed

Ja

ÖFOS 2012

103026 Quantenoptik

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/961bbfa4-e364-4952-a47f-cc60cf93e3f5