Laser Projector & High Freq Laser Source

[clurado]

High all , i am electrical engineer & fpga expert & new to laser scanners .

i am trying to build amateur laser projector with X-Y Scanning .

i prepared hexapod mirrors and attached them to the motors and built XY Scanning unit . but my 10mw red laser doesnt enough power for scanning . so i must use higher power than this .

the solution came from modulation frequency in need . i read some major topics in this section and received good informations about laser beam modulation. hower something still need to be answerd .

is the normal 100mw laser diodes are capble to be switched on & off with frequency about 1Mhz ?!

with resolution of 320x24 and 20fps i need a 1.5Mhz beam modulation . so is the laser diode right choise for this or not ?

i searched for 22x DVD-RW laser diod and i know its about 200 mw power with modulation frequency about 231Mhz so is it right for me ?!


Thanks
Clurado.

 

[anselm]

Hello and welcome to LPF!

Most people on this here forum are more interested in handheld pointers to pop
ballons with. You should go visit the Photonlexicon. Over there it's all about shows/projectors.

 

[Grix]

Laser diodes don't have a rated modulation frequenzy, you can run them any way you want. There are two types of modulation in laser modules, TTL (on/off) or analog (gradual power change from off to fully on).

For decent starting visibility I would have at least 50mW green or at least 200mW red or blue.

 

[Cyparagon]

Almost all laser projectors use vector graphics in lieu of raster. Resolution is not a stat. They're generally rated in power, speed, and/or angle. The modulation speed for this application depends on the image projected, but is generally 10-30kHz or less.

Also, don't forget to add fog.

 

[Bionic-Badger]

What did you use for your slow-axis hex-mirror apparatus? I've got some parts for that kind of thing as well, but haven't figured out a good slow-axis given the sweep of the fast-axis.

For your modulation, I would just send out TTL modulation for now, maybe amplifying it if your FPGA output voltage is too low. A good place to start is to buy a cheap green lab laser that has a TTL input and using that. It'll be somewhat hard for you to get good modulation for a raster-ish display, given the number of pixels and a decent framerate.

Also take a look at what Sltvm2007 is doing with his raster laser display.

 

[Benm]

Switchin at 1 MHz will not be a problem for the laser diiode itself at all. The probkem is designing a constant current source that can keep up with that speed. Most opamp designs just wont cut it, but two-transistor based current sources can easiy match MHz speeds if designed properly.