Image Evaluation of the High Resolution VUV Spectrometer at SURF II by Ray Tracing

Area of Science:

• Spectroscopy
• Optical Physics
• Synchrotron Radiation

Background:

• A high-resolution Vacuum Ultraviolet (VUV) spectroscopic facility has been operational at the Synchrotron Ultraviolet Radiation Facility (SURF II) at the National Institute of Standards and Technology (NIST).
• The facility utilizes a sophisticated optical setup including three cylindrical mirrors and a concave grating spectrometer in an off-plane Eagle mounting.

Purpose of the Study:

• To prepare for the installation of an array detector by developing a ray tracing program.
• To analyze and optimize the spectral image quality, specifically line widths, of the VUV spectroscopic facility.
• To evaluate the achievable spectral widths for VUV spectroscopy using an array detector.

Main Methods:

• Development of a ray tracing program to simulate optical performance.
• Construction of spot diagrams by plotting ray intersections with the image plane.
• Investigation of parallel and tilted entrance slit configurations relative to the grating grooves.
• Estimation of spectral widths for recorded images on an array detector.

Main Results:

• Ray tracing simulations and spot diagram analysis were performed.
• It was demonstrated that tilting the entrance slit can reduce spectral image line widths.
• Estimated spectral widths of 0.41 pm to 0.88 pm in first order were achieved for the 40 nm to 120 nm wavelength region.

Conclusions:

• The VUV spectroscopic facility at SURF II can achieve high spectral resolution.
• Optimizing the entrance slit configuration is crucial for minimizing spectral line widths.
• The facility is well-suited for VUV spectroscopy applications requiring precise spectral measurements in the 40-120 nm range.