Mid-wave infrared multi-order SPPs resonance by exciting multi-order diffractions in 1D Dammann gratings

Area of Science:

• Photonics and Optoelectronics
• Materials Science
• Infrared Technology

Background:

• Mid-wave infrared photodetectors are crucial for various applications.
• Surface plasmon polaritons (SPPs) offer unique sub-wavelength localization for infrared detection.
• Broadband response is a key requirement for many infrared photodetector applications.

Purpose of the Study:

• To design Dammann gratings (DGs) for enhanced surface plasmon polaritons (SPPs) resonance.
• To achieve multi-order SPPs resonance for broadband absorption in infrared photodetectors.
• To investigate the polarization tolerance of the designed SPP structures.

Main Methods:

• Designed one-dimensional (1D) metal/dielectric Dammann gratings.
• Utilized non-sinc function modulated diffraction fields to excite SPPs resonance.
• Varied diffraction slit spacings to control phase differences and achieve multi-order resonance.

Main Results:

• DGs with a 27.3 μm lattice constant generated 2-4 orders of strong diffraction intensity (4-5 μm range).
• Achieved multi-order resonance-enhanced absorption of SPPs.
• Demonstrated improved SPPs response tolerance to polarization angle variations across a broadband spectrum.

Conclusions:

• The developed multi-order SPPs resonance-enhanced structure shows significant potential for infrared detection.
• This approach facilitates the development of large-scale infrared photodetector units.
• The DGs offer a promising route towards broadband, polarization-tolerant infrared photodetectors.