Light Sabres
The 'light sabre' of the 'Star Wars' franchise is something of an oddity. Essentially a glowing sword blade comprising some incorporeal material that allows the user to cut or burn through opponents.
It has often been pointed out that a laser beam cannot be used to create this effect- a laser shone from the handle cannot be compelled to 'stop' at a fixed distance to create a blade of finite length. It is also frequently suggested that the path traced out by a laser beam doesn't glow in the way usually portrayed. This isn't quite true however- in a vacuum certainly, the path of a laser beam is invisible, but a sufficiently energetic laser will ionise air to create a convincingly visible beam in the atmosphere (http://www.youtube.com/watch?v=t65_JJrLFZ8&NR=1).
Recent advances in computer controlled lasers have demonstrated the ability to project images in 3-dimensional space (http://www.aist.go.jp/aist_e/latest_research/2006/20060210/20060210.html). The technique uses a lense to focus a laser beam onto a chosen point in space, creating a plasma 'flashpoint'. Since the focal point of the laser can be moved rapidly, it is possible to create a large number of such flashpoints almost simultaneously.
An effect comparable to the 'light sabre' could thus be created relatively simply by generating a line of flashpoints by rapidly cycling the focal length of a laser source up and down the intended length of the 'blade'. See figure 1:
Figure 1: Light sabre projection
Creating the nastier destructive effects of the sword is then a matter of increasing the laser's power output. It should be noted that one could not block the 'blade' with another blade- they'd pass straight through each other. Also achieving the required energy and power density in a portable device would be a tall order.
The 'light sabre' of the 'Star Wars' franchise is something of an oddity. Essentially a glowing sword blade comprising some incorporeal material that allows the user to cut or burn through opponents.
It has often been pointed out that a laser beam cannot be used to create this effect- a laser shone from the handle cannot be compelled to 'stop' at a fixed distance to create a blade of finite length. It is also frequently suggested that the path traced out by a laser beam doesn't glow in the way usually portrayed. This isn't quite true however- in a vacuum certainly, the path of a laser beam is invisible, but a sufficiently energetic laser will ionise air to create a convincingly visible beam in the atmosphere (http://www.youtube.com/watch?v=t65_JJrLFZ8&NR=1).
Recent advances in computer controlled lasers have demonstrated the ability to project images in 3-dimensional space (http://www.aist.go.jp/aist_e/latest_research/2006/20060210/20060210.html). The technique uses a lense to focus a laser beam onto a chosen point in space, creating a plasma 'flashpoint'. Since the focal point of the laser can be moved rapidly, it is possible to create a large number of such flashpoints almost simultaneously.
An effect comparable to the 'light sabre' could thus be created relatively simply by generating a line of flashpoints by rapidly cycling the focal length of a laser source up and down the intended length of the 'blade'. See figure 1:
Figure 1: Light sabre projection
Creating the nastier destructive effects of the sword is then a matter of increasing the laser's power output. It should be noted that one could not block the 'blade' with another blade- they'd pass straight through each other. Also achieving the required energy and power density in a portable device would be a tall order.
posted by Iansonuk at 3:10 AM
0 Comments:
Post a Comment
<< Home