[SC Swamp Fox]

I do not agree this will be fail safe. One way I see to outwit this test would be to have in addition to the explosives material present, another item which would give off radiation at the 705-nm wavelength and also at the additional nearby frequencies.

Bingo!

You just rendered the device useless.

[Rebel_Ace]

"Bingo!

You just rendered the device useless."

Well, not exactly. The device could still POSITIVELY identify explosives, as long as they were not "masked" in the manner you describe. It raises the bar, so that "improvised" explosive devices, or other primative or crude devices or raw explosive materials would likely be detected 100% of the time, whereas "professional" or military grade production items might contain "masking" material.

[Drammach]

rendered device useless..

Wrong..
All that has been done is to add a "masking" signature..
The target would still flouresce in the 705 nm range..

The procedure might have some false positives, due to the masking, but there would not be any negatives..

It would still reduce the need to search every piece of luggage in an airport..
Only those with a signature would have to be searched..
Same with vehicles, persons..
Flourescence even on a broad bandwidth would be better than the technology (sniffers) that exist now..