The measurement and analysis of wavefront structure from large aperture ICF optics
Abstract
This paper discusses the techniques, developed over the past year, for high spatial resolution measurement and analysis of the transmitted and/or reflected wavefront of large aperture ICF optical components. Parts up to 400 mm times 750 mm have been measured and include: laser slabs, windows, KDP crystals and lenses. The measurements were performed using state-of-the-art commercial phase shifting interferometers at a wavelength of 633 microns. Both 1 and 2-D Fourier analysis have been used to characterize the wavefront; specifically the Power Spectral Density, (PSD), function was calculated. The PSD's of several precision optical components will be shown. The PSD(V) is proportional to the (amplitude)(sup 2) of components of the Fourier frequency spectrum. The PSD describes the scattered intensity and direction as a function of scattering angle in the wavefront. The capability of commercial software is limited to 1-D Fourier analysis only. We are developing our own 2-D analysis capability in support of work to revise specifications for NIF optics. 2-D analysis uses the entire wavefront phase map to construct 2D PSD functions. We have been able to increase the signal-to-noise relative to 1-D and can observe very subtle wavefront structure.
- Publication:
-
Presented at the 1st Annual Solid-State Lasers for Application To Inertial Confinement Fusion Meeting
- Pub Date:
- May 1995
- Bibcode:
- 1995ssla.meetR....W
- Keywords:
-
- Crystal Optics;
- Fourier Analysis;
- Inertial Confinement Fusion;
- Optical Equipment;
- Optical Measurement;
- Power Spectra;
- Signal To Noise Ratios;
- Solid State Lasers;
- Spectral Energy Distribution;
- Wave Fronts;
- Crystals;
- Frequency Distribution;
- High Resolution;
- Interferometers;
- Laser Windows;
- Lenses;
- Light Scattering;
- Optical Properties;
- Phase Shift;
- Spatial Resolution;
- Wavelengths;
- Optics