Note: Reflection zone plates as highly resolving broadband optics for soft X-ray laboratory spectrometers.

Area of Science:

• Optics and Photonics
• X-ray Spectroscopy
• Plasma Physics

Background:

• Off-axis reflection zone plates (RZPs) are optical elements used for focusing X-rays.
• Traditional RZPs have a narrow spectral bandwidth, limiting their use in spectroscopy.
• Tuning the focused wavelength of RZPs typically requires different optical elements.

Purpose of the Study:

• To investigate the resolving power and relative efficiency of two off-axis reflection zone plates (RZPs).
• To explore the potential of using RZPs for spectroscopy across a wider spectral range than their design wavelength.
• To demonstrate the feasibility of using a single RZP for spectroscopy at arbitrary soft X-ray wavelengths.

Main Methods:

• Experimental investigation of two off-axis reflection zone plates (RZPs).
• Utilizing a laser-produced plasma source for soft X-ray generation.
• Employing controlled misalignment of the RZP to tune the focused wavelength.

Main Results:

• RZPs were confirmed to focus a narrow bandwidth around their design wavelength.
• Misalignment of the RZP successfully tuned the focused wavelength over a broader spectral range.
• A single RZP demonstrated efficient use for spectroscopy at arbitrary wavelengths within the 1 nm to 5 nm range.

Conclusions:

• Off-axis reflection zone plates can be effectively tuned for spectroscopy by controlled misalignment.
• A single RZP can serve as a versatile spectroscopic tool in the soft X-ray range.
• This technique expands the applicability of RZPs in soft X-ray spectroscopy.