Arduino reduces the laser power Its important to mention that I'm noob.
I bought 500mw 405nm TTL module laser(5-12 volt) driver circuit. When I supplied laser with 12 volt, it turns on with max power. but when i connects laser TTL module to arduino (pin 11) in order to control turning on &amp; off of laser through GRBL(CNC machine language) command with full power, the output of laser reduces.

"M05 S0" turns off the laser while
"M03 S255" should turns on the laser with full power as it is turning on with direct 12 volt supply, but its not happening.

so how can I make laser turn on with full power with arduino control? 

Laser I,m using
https://www.amazon.in/gp/product/B071J2W7V8/ref=oh_aui_detailpage_o00_s00?ie=UTF8&amp;psc=1

Laser driver circuit
The first thing I would recommend is to log into your Amazon account and contact the seller. Ask them to send you product documentation.

If the seller is not able to provide any, then you could return the product for a refund or try to figure it out how it works.

According to this document: TTL Laser

TTL modulators emit 100% of their power when a TTL "0" (0 VDC) is input and less than 5% of their power when a TTL "1" (5 VDC) is input.

gre_gor's comment about trying a simple PWM sketch sounds like an excellent place to start.