Background

High-power laser systems require high-performance optics that need to be continuously inspected for damage.  High-resolution (micron scale) imagery over large areas (~1 cm2) can be done by taking individual high-resolution images of a small area (~1 mm2) and then stitching them together at their boundaries.  To achieve this, the imaging camera must scan the large image and then take sequential images that are later stitched together.  The limitations of this acquisition approach is that current conventional techniques require a bright light, pausing the scan at each image point, and the capturing of images can be an extremely slow process (i.e., hours instead of minutes).  To substantially reduce the time to produce images with sub-micron resolution, a novel strategy is needed.

Description

LLNL’s novel approach is to use a continuous moving camera with a scan speed of >1 mm/sec and a frame rate of 100 frames per second.  The key is to have a light source that flashes with a duration of one nanosecond, thus essentially freezing the image with no blur.  Clear images of high resolution can then be captured through a high-magnification objective lens (reflection mode) or through the sample (transmission mode) at the rate of one image per second or faster.  These images are then stitched together for a high-resolution image of the entire field of view.

Image
Advantages
  • Value Proposition:  Greater than two orders of magnitude faster (~360X faster) than current methods -> reduce image production time of a 1-cm2 sample from 25 hours to 4 minutes.
  • Use of short light pulses rather than continuous light sources -> large area sample can be taken in a substantially reduced time
  • Higher throughput for optical inspection equipment in semiconductor industry
Potential Applications
  • Semiconductor inspection
  • High power lasers
  • Laser damage performance optics
Development Status

Current stage of technology development:  TRL 2 (Technology concept and/or application formulated)

U.S. Patent No. 11,624,710 Fast Image Acquisition System Using Pulsed Light Illumination and Sample Scanning to Capture Optical Micrographs with Sub-Micron Features issued 4/11/2023

Reference Number
IL-13403
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