Motorised Stage for laser

Question

The problem

I want to be able to move the direction a laser is pointing.

This means I need to have motorised rotation of the laser head in the x direction and in the y direction. I am unsure of the best way to do this.

Currently 6 axis motorised stages are available from Thorlabs but cost on the order of £7000. This is also overkill for what I need.

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Long explanation

I'm a physicist and I'm building an experimental set up. I work on nanoparticles that have implications for optoelectronics & solar cells.

I'm currently making an automated system to test samples which are roughly 15cm by 15cm (and have the nanoparticles on them). I need to scan the laser across the whole sample, taking measurements at specific coordinates on the sample.

The laser is coupled to an optical fibre - we can assume the light is collimated. How best do I raster the laser light around the sample?

Is there some sort of computer controlled jig which might be able do this, are there better solutions?

Hopefully the setup can be entirely robotic - i.e. I place the the sample in, and all the measurements are automated - I'm struggling with automating the laser direction.

Edit:

Some further details

• The laser must stay fixed in position i.e. it is only allowed to pan and tilt. i,e a simple x y stage of the same dimensions of the sample would not be appropriate.

• Almost any amount of jitter is allowed when the laser moves.

• The speed of operation is not important.

• The laser does NOT need to remain perpendicular. All that matters is the spot hits a rough area (say around 2-3 cm by 2-3 cm).

Answer 1

You have several options, and which you select might depend not only on cost, but also on the requirements for your system which you haven’t stated. For example, how much jitter is allowed while the laser moves? How fast must it move? Does the laser need to stay perpendicular to the target sample?

The easiest solution to implement, if the laser does not need to keep its angle to the target constant, would be a pan-tilt mechanism. You can find these with steppers or servo motor controllers.

Another solution is a two-axis stage. This would keep the axis of the laser consistent while translating it across the target. Many stages like this can be found online. Again, they can come with steppers, servos, or even pneumatic controls.

Finally, you could keep the laser aligned with and translating across the target by implementing a series of piezo-controlled mirrors. This is pretty common in laser research, but could be complex to implement.