Adjustable bandpass filter employing a prism

Area of Science:

• Optics and Photonics
• Spectroscopy Instrumentation

Background:

• Prism-based optical systems are fundamental in spectroscopy.
• Conventional methods for managing spectral orders in grating spectrometers can be complex.
• Variable bandpass filtering is crucial for precise spectral analysis.

Purpose of the Study:

• To develop and characterize a novel prism-based system for variable, wide bandpass filtering.
• To demonstrate the system's utility in preventing overlapping orders in grating spectrometers.
• To highlight the advantages of this system over conventional approaches.

Main Methods:

• A prism system was designed with adjustable slits in the focal plane to define the bandpass.
• Mirrors were incorporated to redirect the beam through the prism, ensuring an undispersed image.
• The system's performance was evaluated, particularly in the context of grating spectrometers.

Main Results:

• The developed system functions as a variable, wide bandpass filter for the visible and near-infrared spectrum.
• Bandpass tunability is achieved by adjusting the slit pair.
• An undispersed image of the entrance slit is formed for all wavelengths within the selected bandpass.

Conclusions:

• The novel prism system offers an effective and tunable method for wide bandpass filtering.
• This system presents significant advantages for applications requiring the suppression of overlapping spectral orders, such as in grating spectrometers.