Chevron-Type Dielectric Filter Set for Efficient Narrow-Band Laser Line Rejection in Raman Microspectrometers

Abstract

A chevron-type dielectric bandpass filter set is described which combines laser line rejection by a factor >10⁸ with a high throughput of Raman scattered light (70%). The rejection bandwidth is 60 cm⁻¹ full width at half-maximum. Stokes and anti-Stokes Raman spectra can be recorded simultaneously from approximately 20 cm⁻¹ from the laser line. The filter set, moreover, takes care of efficient coupling of microscope and spectrometer, replacing an otherwise necessary beamsplitter.