laser pointer turned on LEDs while it was pointed at them

[petters]

okay so i was bored and decided to point my laser (1000w 447nm) at an LED flashlight, i always wondered what would happen but was afraid that the laser would burn out the LED or something. I tried it and when the laser got closer to the LED i could see the light turning higher until it was fully on when the laser shined on it. I took the batteries out and the same effect happened, and was just wondered if anyone had an explanation for this? :thinking: thanks

 

[Jimmymcjimthejim]

What you are seeing is the fluorescence of the phosphor in the white LED. Remember, white LEDs are just blue LEDs with a phosphor coating to make an even spectrum of light. When you shine your blue laser on the LED, you are exciting the phosphor in a similar way that will appear to make the LED turn on. Remember, however, that this process is nowhere near 100% efficient, so you must be careful to not shine the laser on the LED for too long or you will burn the LED out. On a side note, I remember FireMyLaser has a video of a blue laser burning out an LED.

 

[petters]

i have learned something new today that i will probably never forget, thanks

 

[DrSid]

You can make red leds look like they are on bu shining 1mW red laser on them. I like it very much ..

 

[BShanahan14rulz]

LEDs can work backwards too, just not very efficiently. light in = current out.