Vaibhav,

One thing you may try is to put a "calibrated" beam splitter into the
optical path.  A fraction of the beam would be diverted by 90 degrees,
and you can place either your detector or your camera at the output of
that beam, and the other instrument would read the beam that goes
through the beamsplitter.  You will have to calibrate the intensity of
the light at the end of the splitter that you make the intensity
measurement as some light is absorbed by the splitter.  Once you know
how much is absorbed you can calculate the actual intensity simply.
If you want to get fancy, you can also get a holder for the splitter
that can swing in and out of the optical path, which will give you
more light in the ccd if you would need that.  All of these items are
available at the larger optical supply companies.

Brad

_________________________________

Brad Cantos
brad.cantos@holage.com
http://holage.com

LinkedIn: http://www.linkedin.com/in/bradcantos



On Mar 1, 2009, at 11:31 AM, vaibhav mathur wrote:

> hi all,
>
> I am trying to monitor the laser intensity at the output end of my
> MEMS device. I have a problem as I have to be able to see the output
> on a ccd camera, and measure the intensity at the same time.
> Currently, I first align using a ccd camera, remove it from the beam
> path, introduce a photodetector in the beam path,  measure
> intensity, repeat the steps again and again for each measurement.
> This is an extremely tedious and time consuming process. Any
> suggestions on kind of optics I can use two get both measurements at
> the same time (CCD+photodetecotr) will be appreciated.  I monitor
> the intensity at high frequencies of order 300Khz, thus have to use
> a silicon photodetector, CCD camera is only for visual alignment
> regards
>
> Vaibhav Mathur