Axial hyperchromatic spectrometers: compact solutions for spectral analysis in the NIR range

Area of Science:

• Optical Engineering
• Spectroscopy
• Photonics

Background:

• Traditional infrared spectrometers often face limitations in size and cost.
• Developing compact and efficient wavelength-scanning systems is crucial for advancing portable and field-deployable spectroscopic applications.

Purpose of the Study:

• To design and implement compact, fully axial wavelength-scanning systems for infrared spectroscopy.
• To investigate both purely refractive and hybrid refractive-diffractive optical element (DOE) designs.
• To evaluate the performance and feasibility of these systems for near-infrared (NIR) spectrometry.

Main Methods:

• Utilized a hyperchromatic optical design with a simple on-axis structure and a point detector.
• Developed two implementations: a purely refractive system and a hybrid system with DOEs.
• Achieved wavelength scanning through axial shifting of an optical element.

Main Results:

• The hybrid spectrometer demonstrated superior performance, maintaining a resolution of approximately 30 nm across the 1000-2200 nm range.
• Achieved a compact design with a minimal adjustment range of 4.3 mm for the tunable optical component.
• The system achieved a minimum equivalent Abbe number of 0.22 and an axial chromatic spread of 90 mm.

Conclusions:

• Axial wavelength-scanning systems are feasible for NIR spectrometry, offering a compact and cost-effective alternative.
• The hybrid refractive-DOE approach provides enhanced performance and miniaturization potential.
• These systems have potential applications in various scientific and industrial fields requiring efficient spectroscopy.