high speed photography anyone? with pulse lasers!!

S

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Just thought I'd post a 532nm laser backlit image shot with a pulse laser.

The shadowgraph is annotated and what you are seeing is a shock wave being emitted by ablating plasma.

Whats most interesting is that this was shot with a 350D camera :eek:

Exposure is controlled by the intensity of the pulse laser. Nominal temporal resolution is approx 0.4ns with per pulse energy of 0.1 J delivering power in the gigawatt range.

Len is a custom optics bench lol. the entire pulse is shot directly on the 350D sensor. A 5nm band pass filter isolates the laser pulse from any other light.

Nanosecond triggering kit allows the shot to be taken precisely at a certain time after the shock forms.

shadow-for-presentation-copy.jpg
 
I dont know what you just said... But did you hear the whoosshhh? as it went over my head?:lol:
 
Ow my head hurts. :(
Can you explain in lehmans terms?
 
Basically you know those water droplet shows are frozen in time by a short flash from a flash gun? This is similar to that. flash duration from a 580exII is about 1.2ms , This laser acts as a flash as well but the duration is 0.4ns.

Clearly the shorter pulse can freeze faster things, that shockwave in the image is moving at 40km/s .

But to obtain a proper exposure in 0.4ns instead of 1.2ms, the power that the laser delivers is just sublime lol.

The shock wave itself is generated buy passing a 1.4million amps through wrapping foil in 240ns . This creates the plasma shock you see in that shot.
 
jesus!!
I hope you didnt drain the UK of power for 1.4million amps?!!?

I kinda get it now! Didnt know you could light with a laser though!
0.4ns is mental fast!
 
I followed it all Sid. As for you other lot....education today isn't what it used to be

:exit:

:popcorn:
 
that sounds awesome, whats the purpose of your experiments? are you analysing the way shockwaves behave at nano scales?

(I followed it Mr E nowt wrong with todays education, just depends fow far you followed physics)
 
I think it also depends on how tired the reader is at the time :p
I think I understand, but I'm going to try again in the morning :)
 
david1701 said:
that sounds awesome, whats the purpose of your experiments? are you analysing the way shockwaves behave at nano scales?

(I followed it Mr E nowt wrong with todays education, just depends fow far you followed physics)
Click to expand...

The equipment isn't nano scale at all. The shock is 1cm wide.

The aim of this experiment was to produce a 2d shock from a metal strip. Its difficult to explain in a nutshell I'm afraid.

If you want to see photos of the kit have a look here

http://thezeitgeist.eu/?p=280

http://thezeitgeist.eu/?p=267

sid
 
oh ok I misinterpreted the plasma bit, thought you were looking at how shockwaves work on a smaller scale, is it the paticular properties of plasma your looking at, or should I just go away cos physics isn't my thing :D
 
david1701 said:
oh ok I misinterpreted the plasma bit, thought you were looking at how shockwaves work on a smaller scale, is it the paticular properties of plasma your looking at, or should I just go away cos physics isn't my thing :D
Click to expand...

We are mainly looking at shockwave lauching mechanisms and their shape.

The plasma is by product of putting 1.5Million Amps through the wrapping foil.

Think about how much current melts yours 13A fuse to draw a comparison.

sid
 
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