Set a Power Meter's Wavelength, Range, and Zero Offset Parameters for Improved Accuracy
A power meter should be configured specifically for the light incident on the power sensor. Three important power meter parameters to set are the center wavelength of the light, the maximum optical power the sensor will measure, and the zero offset resulting from the detection of ambient light.
The procedure for setting these three parameters, and some things to consider while configuring them, are demonstrated and discussed using a PM400 optical power meter, an S3FC520 fiber-coupled laser source, and an S120C optical power sensor.
Always follow your institution's laser safety guidelines. Unlike the low-power source used in this demonstration, other laser sources may be damaged by back reflections. Many stray reflections, which can endanger colleagues and the laser, can be avoided by blocking the laser beam when it is not needed.
Avoid Screw-Length Pitfalls When Securing a Post Holder to a Table or Base
A common, unfortunate result of securing a post holder to a base or optical table is threads poking up through the bottom of the post holder. These exposed threads limit the height adjustment range offered by the post holder. Additional frustrations can result after rotating the post in the post holder, since this can unintentionally screw the post onto the exposed threads.
The solution is to keep screw length in mind when selecting a setscrew or cap screw to secure a post holder. In this video, observe consequences unfold due to threads projecting up from the bottom of the post holder, and learn techniques for overcoming this problem. The options of securing a post holder to a base or directly to the table are also compared.
Aligning a Linear Polarizer's Axis to be Perpendicular or Parallel to the Table
The beam paths through many optical setups are routed parallel to the optical table. When this is the case, the plane of incidence and the p-polarization are typically oriented parallel to the table's surface, while the s-polarization is perpendicular. Therefore, polarizers aligned to pass p- or s- polarized light effectively have their axes aligned to be parallel or perpendicular, respectively, to the table's surface.
A procedure for optically aligning the axis of a polarizer to be perpendicular to the optical table is discussed and demonstrated using optical power readings of light transmitted through the polarizer. Then, three options for aligning the axis of a polarizer to be parallel to the table are outlined. The method of crossed polarizers is demonstrated. Tips and tricks for obtaining more precise measurements are also shared.