Hello, we are using DMD with the laser to do beam shaping. I have some questions about the power efficiency.
(1) DMD is designed for visible light but our laser is infrared (1064nm). Based on the energy efficiency measurement, we found the result is only about 20%. Is it normal??
(2) I tried to find sources to explain this big loss and found some material for window transmission. Is the data from this transmission from input to output (2 passes through the windows and one bounce off the DMD)?
(3) Does diffraction cause a severe energy loss? Can you tell me about the fraction of energy in the main order?
The diffraction efficiency can cause this loss. It depends on the specific DMD you are using. The wavelength and incident angle as well as the tilt angle and mirror pitch of the device play an important role. What DMD are you using?
There are DMD's than can be purchased that have a NIR coating. The curves shown on the website are for a single pass through the window AR coating. However, the Window AR coating does not explain the loss of 80% of the light.
Since you are using a laser, then diffraction efficiency can be a very important factor. You may need to adjust the illumination angle or more capture more diffraction orders of the laser to increase your efficiency.
I would encourage you to read the application note "using lasers with DLP". It can be found here:
All content and materials on this site are provided "as is". TI and its respective suppliers and providers of content make no representations about the suitability of these materials for any purpose and disclaim all warranties and conditions with regard to these materials, including but not limited to all implied warranties and conditions of merchantability, fitness for a particular purpose, title and non-infringement of any third party intellectual property right. TI and its respective suppliers and providers of content make no representations about the suitability of these materials for any purpose and disclaim all warranties and conditions with respect to these materials. No license, either express or implied, by estoppel or otherwise, is granted by TI. Use of the information on this site may require a license from a third party, or a license from TI.
TI is a global semiconductor design and manufacturing company. Innovate with 100,000+ analog ICs andembedded processors, along with software, tools and the industry’s largest sales/support staff.