Learning Forum

[oliver.grimm]

As per documentation, a length unit is defined in a ZBF file. Yet the the waist of the pilot beam shall be given in lens units. Is that indeed correct? This is surprising since the lens unit might be unknown when the ZBF is generated. Also the pilot beam z position and Rayleight length seem to be not in lens units according to documentation.

Also the wavelength shall be given in lens units, which is not in agreement with my own experience: when working with millimeter lens unit and a wavelength set in ZEMAX of 15 micrometer, I had to specify the wavelength in the ZBF file as 15e-6, otherwise I got a warning that the wavelengths do not match.

Could the exact units for the ZBF entries that have a length please be clarified.

Thanks, Oliver.

[Ethan Keeler]

 

Hi Oliver,

Thanks for the question! I think what might help here is to dissect the structure of the ZBF file itself. If you look at its structure (Zemax Beam File (ZBF) text format (ansys.com)), you’ll find this documentation:

The important part here, highlighted above, is a property that indicates the lens units (mm, cm, in, etc.). When OpticStudio reads the ZBF file, it does so considering the units indicated for the values in the files. If the lens system that the ZBF is being imported into has different units, then an appropriate conversion will happen for the properties of the beam. Unless noted otherwise, every distance measurement should be in lens units. Therefore, it is not necessary to know the lens units for the intended optical system, only the lens units at the time of ZBF creation.

For the file where you receive a warning about the wavelength mismatch, do you know if the sixth-lined parameter in the ZBF was units = 3? This would tell OpticStudio to expect meters.

Ethan

 

[oliver.grimm]

Thank you for these comments.

So what is labeled Units in the format specification should actully read Lens Units. This line thus defines what lens unit means for this particular file and therefore all of dx,dy,zx,Rx,wx,zy,Ry,wy and lambda are measured in this unit. The file with the warning had units=3, which now also makes sense.

From the wording I erroneously deduced that Lens Units and Units mean different things in that file.

[Ethan Keeler]

Hi Oliver,

Yes, in this context, Units = Lens Units, so your understanding is exactly correct.

Ethan