Can Laser Intensity Stabilization Be Improved for Precise Measurements?

In summary, a setup involving a collimated laser (Thorlabs model CPS180), two polarizers, a beam splitter, and 2 photo-diodes is being used to measure the intensity of the laser via LabView. However, during the first hour of measurement, the intensity varies by 0.2mV without any changes to the components. It increases for the first half hour, then decreases for 15 minutes before stabilizing. The laser needs to be stable to within a few hundredths of a milliVolt for the experiment. It is suggested to check the supply voltage and polarization ratio of the laser, and to ensure it is operating within specifications. A resource for LD characteristics is provided. It is also mentioned that most measurements were
  • #1
ssmoke
2
0
I'm working with a setup involving a collimated laser (Thorlabs model CPS180), two polarizers, a beam splitter, and 2 photo-diodes. While measuring the intensity of the laser via LabView, without changing any of the components, I find the intensity varies by 0.2mV for the first hour of measurement. it increases for about the first half hour, then decreases for the next 15 minutes before even starting to stabilize. This seems like very odd behavior, even if the laser needs some time to warm up.

For my experiment, it is important that the laser be stable to within a few hundreths of a milliVolt. Do you think the problem is with my laser, photo-diode, or even the LabVIEW program?

If the problem is with my laser, is there a simple way to stabilize the intensity?
 
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  • #2
You might want to check the supply voltage to the laser to make sure it isn't changing, hence changing your wavelength and power a bit. I'm also not sure how the polarization ratio in these lasers changes as they warm up. Are you monitoring it after you pass it through your optics?
 
  • #4
I think most of my measurements have been taken with at least one polarizer.
 
  • #5
You mentioned how much the laser intensity changed, but not the average value (i.e the relative change). How large was it?
 

What is laser intensity stabilization?

Laser intensity stabilization is a process that involves maintaining a constant intensity or power output of a laser beam. This is typically achieved through the use of feedback control systems that adjust the laser's parameters to compensate for any changes in the environmental conditions or internal components.

Why is laser intensity stabilization important?

Laser intensity stabilization is important because it ensures consistency and accuracy in the output of a laser beam. This is crucial in applications where precise and stable laser power is required, such as in scientific research, industrial processes, and medical procedures.

What are the benefits of laser intensity stabilization?

The benefits of laser intensity stabilization include improved accuracy and precision, reduced measurement errors, increased reliability and repeatability, and extended lifespan of the laser components. It also allows for better control and manipulation of the laser beam, which is essential in many applications.

How does laser intensity stabilization work?

Laser intensity stabilization works by using a feedback control loop that continuously monitors the laser output and makes adjustments to the laser's parameters, such as its current, temperature, or cavity length, to maintain a constant intensity. This is often achieved through the use of electronic or mechanical components, such as photodiodes, piezoelectric devices, or acousto-optic modulators.

What are some common techniques used for laser intensity stabilization?

Some common techniques used for laser intensity stabilization include the use of servo control systems, optical feedback loops, and active power control methods. Other methods may involve the use of external reference signals or locking the laser to a stable reference cavity. The choice of technique depends on the specific application and requirements of the laser system.

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