×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Optical systems engineering FAQ

Optical System Engineering

Electro-optical Oddities by IRstuff
Posted: 23 Feb 06

>> Standard CCD and CMOS cameras can "see" 1570 nm sources -- reason is unclear, since silicon cuts off at around 1200 nm and the absorption depth at 1570 nm is something like many centimeters, way thicker than the 20 um silicon die thickness.  One possible explanation is that the SiO2 is known for 2nd harmonic generation and that's what we're seeing.

>> The Sensors Unlimited 320M InGaAs imager, with a known cuton around 900nm can "see" 650 nm signals, sort of.  Turns out that the InP substrate on which the InGaAs detector is built is responsive to 650 nm, so the generated carriers are able to move into the InGaAs epi layer and behave like normally generated photoelectrons.  Since the electrons diffuse quite a ways, it's no good for serious beamwidth measurements, but can be used for beam alignment tasks with 1570 sources.

Back to Optical systems engineering FAQ Index
Back to Optical systems engineering Forum

My Archive


Resources

Low-Volume Rapid Injection Molding With 3D Printed Molds
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Design for Additive Manufacturing (DfAM)
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a part’s function at the center of their design considerations. Download Now
Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close