Properties and potential applications of reflection focusing and dispersion plane gratings

Plane gratings are widely used as dispersion elements in spectral analysis from the infrared to x-ray regions. This study proposes an optical element, consisting of only a reflection focusing and dispersion plane grating (RFPG) designed for a specific wavelength. A raytracing simulation and a visible light experiment were performed to verify the focusing and wavelength dispersion properties of the proposed RFPG. The raytracing simulation result shows that the designed 635 nm RFPG has a spectral resolution (λ/∆λ) of 423 (linear dispersion = 493.8 eV/m) under specific conditions. Additionally, in the visible light experiment, the spectral resolution of 423 (linear dispersion = 493.8 eV/m) and band range of ±25 nm were obtained at the target wavelength of 635 nm. The experimental results indicate that the proposed optical element, RFPG, exhibits focusing and dispersion properties for a designed wavelength. It is a potential tool for the study of x-ray fluorescence, absorption, and advanced x-ray sources, such as laser wakefield Betatron x-ray sources.