Related Experiment Video
Updated: Jun 6, 2026

A Multimodal Wide-Field Fourier-Transform Raman Microscope
Published on: December 30, 2025
Cross-shaped bandpass filters for the near- and mid-infrared wavelength regions
Abstract:
A photolithographic process has been used to form cross-shaped patterns in 3-μm-thick nickel foils. Patterns with cross arm dimensions in the 10-20-μm range, and with periodicities in the 16-26-μm range, yield self-resonant bandpass filters for wavelengths in the 20-25-μm region. Transmittances as high as 80% were achieved with center wavelength-to-bandwidth ratios (λ(R)/Δλ) of ~5. We present a simple empirical formula that relates the wavelength of peak transmittance, or resonant frequency, with cross dimensions and periodicity.
Related Concept Videos
Passive Filters
Low-Pass Filters
Low-pass filters are designed to transmit signals with frequencies lower than the cutoff frequency, ωc, and attenuate those above it. The cutoff frequency...
IR Frequency Region: Fingerprint Region
The...
IR Spectrometers
IR Spectrum
Transmittance is defined as the ratio of the radiant power passing through a sample to that from the radiation's source. Multiplying the transmittance by 100 gives the percent transmittance (%T), which varies between 100% (no absorption) and 0% (complete...
Infrared (IR) Spectroscopy: Overview
Different compounds display unique properties due to their...
IR Frequency Region: X–H Stretching

