We answered this question on the show...We posed this question to John Tish, Professor of Laser Physics at Imperial College London and Dr. Martin Zaltz Austwick, from University College London...
John - One of my favourite laser scenes in films is in Goldfinger
where James Bond is strapped to a gold table and a laser beam is seen to cut bet
ween his legs, inching closer to his nether regions while Goldfinger says, ďNo Mr. Bond. I expect you to die.Ē High powered lasers are used quite extensively in industry for cutting materials, for example, the metal panels of cars. So that rather eye-watering moment is actually quite plausible. In reality, the lasers are focused with a lens that's quite close to the surface of the material which is to be cut, so as to concentrate the energy into a small region. So, the beam that we see slanting in on the table is not particularly realistic but still pretty fun.
Martin - You have to have a laser at a wavelength where tissue absorbs that particular wavelength, that particular colour. So, if you have a red laser, the main absorber in tissue around that frequency is haemoglobin and haemoglobin is red. In other words, it transmits in the red. It isn't absorbing the red. So using a red laser to cut someone in two is dreadfully inefficient.
Hannah - So Goldfinger, top marks for your realistic use of lasers but if you'd like to frazzle Bondís bits more effectively, we suggest that you decrease your beam length and change your laser colour. Going back to John with his second favourite laser film of all time and there appears to be a theme here. Itís Austin Powers in Goldmember
in which Dr. Evil straps lasers to the heads of sharks or even sea bass. John explains...
John - There's absolutely no reason why you couldnít make a laser waterproof and indeed, underwater lasers are used for imaging and communications. I think the real credibility issue there is the power of the laser shown in that film. The beams that come off them are seen to demolish parts of Dr. Evilís lair. There's totally no way that you could make a high-powered laser small enough so it would fit even on a very large sharkís head.
The most powerful lasers in the world today, the NIF Laser in the US and the Falcon Laser in the UK, are building size. Weíre talking big buildings here with lots of space taken up by the power supplies and the technology for energising the laser. But I guess there's no fundamental scientific reason why they couldnít be miniaturised in the future perhaps based on new technologies. Just look at what has happened to computers, which also used to be building sized. By the way, I thought it might be interesting to note that Dr. Evilís using of the word laser with exaggerated hand quotes is frequently used in laser labs around the world. So itís finally cool to be a laser scientist.