Post on 19-Jan-2016
Femto-science/technology
• From femtosecond chemistry to attosecond physics
• Ultrafast data communications
• Ultrafast imaging
Ever d
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xposu
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Imaging in the millisecond regime[Eadweard Muybridge –Galloping horse, 1887]
Flash photography- microsecond regime
‘Freezing’ of motion using short pulses of light
- e.g. 1 microsecond xenon flashlight
Novel apple sauce! [Harold Edgerton, MIT, 1964]
Prompt imaging in the ultrafast regime
Input
diffuse
snake-like ballistic
snake-like
ballistic
diffuse Output
An ultrashort laser pulse propagating through a scattering medium has ballistic, snake-like and diffuse components.
Images with femtosecond exposures![Valdmanis et al, Michigan]
Photograph of two crossed metal needles
(0.5mm diameter)
The needles viewed through a 6mm slab of raw chicken breast in ordinary illumination
‘Snapshot’ image of the needles using
femtosecond illuminating and
gating pulses
Imaging at terahertz frequencies
• Femtosecond laser pulse illumination of semiconductor switch
• Generation and propagation of terahertz radiation
• Spectroscopy & imaging using T-rays
T-ray image of packaged chip[Martin Nuss, AT&T Bell Labs]
• Plastic overlayer is transparent to T-rays
• Metal leads and silicon chip reflect or absorb T-rays
• 250 micron spatial resolution
Security-imaging with T-rays
Left: Shoe imaged with a standard camera
Middle: T-ray image reveals the presence of a ceramic blade and plastic explosives within the shoe
Right: Removal of sole exposes the hidden items[Image: Teraview]
Imaging of skin cancer using T-rays