Single shot measurement of pulse laser

[prabesh99]

How can I measure the power of a single pulse using the trigger? The powermeter is star bright from Ophir. It does not support the trigger. I want to use LabVIEW to measure the power of a single pulse.  Does anyone have an idea?

[Henrik_Volkers]

Depends on the the sensor you use, and if there are more than one pulse, how fast you need to measure it, .. will get tricky in the femto second scale if you want the pulse shape 😉

In fact a TEC or photocell (with capacior)  will integrate the pulse energy and as such can be used as a measure of the pulse energy.

If you want to measure the pulse and use the pulse itself as a trigger source, the common way is to use pretrigger samples . The ADC samples continously in a ring buffer, and if the trigger condition occures, you can read values before (and after)  the trigger.  

[NIquist]

You are not providing enough information for us to even guess.

What is the frequency and power range of the laser?  What Manuf/Model?

How long is the pulse?  Is it a pulse train or single-shot?

The Starbright is an optical meter.  What sensor(s) do you have for it?  Did you install the LabVIEW drivers for it?

What does a trigger have to do with anything???

[Kyle97330]

What have you done so far?

Have you gone here:

https://www.ophiropt.com/en/f/starbright-power-meter

On that page are links to their StarLab software which installs a COM object, and some LabVIEW code that uses it.  Have you installed that and tried their code?

Can you do what you want in StarLab without involving LabVIEW?

[prabesh99]

Hi! , Yes, I installed the software and LabVIEW code. I cannot do what I want using StarLab. So,  I want to use LabVIEW. I need to measure the average power and standard deviation of power, which I cannot obtain from the power meter.

[prabesh99]

Hi! 

The frequency is 1 KHz and power is 7.5 W. The laser is from Spectraphysics. Its module name is Spitfire (Ti:Sa) . 

The pulse is 100 fs long. It is a train pulse. I have a pyroelectric sensor ( PE50-C ) from ophir. 

Yes, I installed the LabVIEW driver for it. 

I want to measure the single shot power without triggering. I just want to know whether it is possible to measure the single shot without a trigger. 

[Kyle97330]

I've only used the Ophir COM object with thermopiles (i.e. a very slow response) so I can't be sure this will work for you.

I would try this:

Use OpenUSBDevice to get your hDevice number

Run ConfigureStreamMode, with a mode setting of "2" for "Immediate" (i.e. no triggering) and nValue of 1 (1=on).

Run StartStream to start it gathering data

Start running "GetData" in a loop.  The output arrayValue should hopefully be pulse energies and the arrayTimestamp should hopefully be the times of said pulses.