By wavelength:[1]

230-400 nm: Optical sensors, various instrumentation
230-365 nm: UV-ID, label tracking, barcodes
240-280 nm: Disinfection, decontamination of surfaces and water (DNA absorption has a peak at 260 nm)
250-300 nm: Forensic analysis, drug detection
270-300 nm: Protein analysis, DNA sequencing, drug discovery
280-400 nm: Medical imaging of cells
300-400 nm: Solid-state lighting
300-365 nm: Curing of polymers and printer inks
300-320 nm: Light therapy in medicine
350-370 nm: Bug zappers (flies are most attracted to light at 365 nm)[2]

I am beginning to get it now...I am supposed to be looking at the middle range of 200-300 for some reason...and that is related to the POLICE.

I now have to type in a BLUE code: enessa