31 research outputs found
Fine mapping of RBG2, a quantitative trait locus for resistance to Burkholderia glumae, on rice chromosome 1
Bioluminescent imaging of single bacterial cells using an enhanced ilux operon.
The lux operon is a useful reporter for bioluminescence imaging due to its independence of exogenous luciferin supply, but its relatively low brightness hampers the imaging of single cells. This chapter describes a procedure for the imaging of individual Escherichia coli cells using an improved ilux operon. The enhanced brightness of ilux enables long-term bioluminescence imaging of single bacteria with high sensitivity without the requirement for an external luciferin
Tracing the phase of focused broadband laser pulses
Precise knowledge of the behaviour of the phase of light in a focused beam is
fundamental to understanding and controlling laser-driven processes. More than
a hundred years ago an axial phase anomaly for focused monochromatic light
beams was discovered and is now commonly known as the Gouy phase. Recent
theoretical work has brought into question the validity of applying this
monochromatic phase formulation to the broadband pulses becoming ubiquitous
today. Based on electron back-scattering at sharp nanometre-scale metal tips, a
method is available to measure light fields with sub-wavelength spatial
resolution and sub-optical cycle time resolution. Here we report such a direct,
three-dimensional measurement of the spatial dependence of the optical phase of
a focused, 4-fs, near-infrared laser pulse. The observed optical phase deviates
substantially from the monochromatic Gouy phase - exhibiting a much more
complex spatial dependence, both along the propagation axis and in the radial
direction. In our measurements, these significant deviations are the rule and
not the exception for focused, broadband laser pulses. Therefore, we expect
wide ramifications for all broadband laser-matter interactions, such as in
high-harmonic and attosecond pulse generation, femtochemistry, ophthalmological
optical coherence tomography and light-wave electronics.Comment: See journal reference for supplementary materia