Optical modeling techniques for multimode horn-coupled power detectors for submillimeter and far-infrared astronomy

Area of Science:

• Physics
• Optical Engineering
• Electrical Engineering

Background:

• Submillimeter and far-infrared detectors often use multimode horns coupled to thin conductor absorbing films.
• Accurate modeling of partially coherent optical behavior is crucial for detector performance.

Purpose of the Study:

• To develop and validate a model for the full, partially coherent optical behavior of multimode detectors.
• To demonstrate the equivalence of mode-matching and Green's function methods for absorber modeling.
• To show how component scattering matrices can be cascaded for overall detector response calculation.

Main Methods:

• Extensions of mode-matching techniques were employed.
• The absorber was modeled as a resistive sheet.
• Mode-matching and Green's function methods were compared for scattering matrix calculation.
• Scattering matrices of different components were cascaded.

Main Results:

• The resistive sheet model for the absorber was validated.
• Equivalence between mode-matching and Green's function methods was demonstrated.
• A method for cascading scattering matrices to determine overall detector optical response was shown.
• Simulations of a square absorbing film in a circular waveguide were presented.

Conclusions:

• Mode-matching techniques provide a robust framework for modeling multimode detector optical behavior.
• The cascaded scattering matrix approach enables accurate prediction of detector performance.
• This modeling approach is applicable to various detector designs and components.