The PSM is an autocollimator when the objective is removed because the pigtailed SM fiber laser is collimated inside the PSM. As an autocollimator the PSM has a capture range of +/- 1.5 degrees and an angle sensitivity of slightly less than 1 second of arc (about 4 microradians). The collimated beam is 8 mm in diameter, so it is particularly useful for measuring the wedge in small windows and prisms. The bright (MAX) laser sitting produces an easily visible collimated beam making it east to align a mirror to the PSM initially. Once the return is captured the laser power is greatly reduced for measurement.
OPG sells a mount for using the PSM as an autocollimator as shown in the picture that provides tip/tilt adjustment and easily mounts to an optical breadboard via a stout 1” post. The right angle attachment rotates the beam 90 degrees to pair up with the angle adjustments on the mount.
If there is a need for greater angle sensitivity a beam expander is available to give either 5 or 10x greater sensitivity at the expense of proportional field of view size and an increase in size of about 12 cm perpendicular to the PSM body.
The standard autocollimator package is about 18 x 10 x 8 cm and weighs about 1 kg. It is completely powered and controlled by the laptop computer sold with the PSM. The small size, weight and ease of adjustable mounting make the package ideal for OEM incorporation in other equipment.