Reimaging UV Laser Beam Profiling

By Kevin Kirkham, Sr. Manager, Product Development, Ophir-Spiricon

Ophir Photonics offers a number of solutions for profiling UV laser beams. Spot sizes from 0.15mm to over 25mm can be safely profiled without the risk of camera sensor damage or degradation. Laser beam analyzer accessories based on wavelength conversion materials permit spatial profile analysis of UV lasers with wavelength in the range of 193nm to 360nm.

  • Wavelengths from 190 to 360nm
  • Spot sizes from 150μm to 30mm*
  • Energy density from 50μJ/cm² to 0.6J/cm²**

* Maximum measurable spot size is 4 times the CCD active area up to a maximum of 30mm diameter.
** Laser fluence exceeding 30mJ/cm^2 requires optional beam splitter: BEAM SPLITTER FOR X4 UV, P/N SPZ17007

 

Three types of C-mount UV accessories are offered: 4X expander, 4X reducer, and 1:1 UV imaging system. The UV beam profiling accessories attach directly to Cmount type cameras with 4.5mm or 12.5mm sensor spacing. Each comes with its own spatial calibration value so that Ophir’s BeamGage beam profiling software results can accurately reflect the magnification of the reimaging optics.

Three UV Converter Optics & Imaging System

Figure 1. 1:1 UV Converter P/N SPZ17023
Figure 1. 1:1 UV Converter P/N SPZ17023

Figure 2. 4X Beam Expander / UV Converter with<br />
UV Image Converter, PNs SPZ17019 and SPZ17022
Figure 2. 4X Beam Expander / UV Converter with UV Image Converter, PNs SPZ17019 and SPZ17022

Figure 3. 4X Reducer UV Image Converter,<br />
PN SPZ17024
Figure 3. 4X Reducer UV Image Converter, PN SPZ17024

The c-mount UV conversion re-imaging products consist of four main components:

  1. Conversion crystal. This crystal is specially doped Nd:YAG and is cut and polished to be very thin, <50um.
  2. Filter blocks a UV light that was not converted to visible.
  3. Visible image is relayed to the image plane with the use of some lenses.
  4. Camera sensor plane (not provided) converts visible image to an electronic one.

 

Reimaging UV Laser Beam Profiling

Available UV conversion / re-imaging systems include: 4x reduction, 4x expansion, or 1:1 re-imaging of the UV profile. Converter uses C-mount adapter threads to connect to camera. The converter design requires a CS (4.5mm) or SP (12.5mm) camera. They will not work with C-mount (17.5mm sensor spacing) cameras.

In addition to the three C-mount options, we offer solarized glass and doped YAG crystal UV conversion targets for use with our CCTV lens reimaging options. These conversion materials require one of our CCTV lenses and mounting hardware to construct a laser beam re-imaging system. Crystal UV imaging plates are more spatially uniform and exhibit higher sensitivity than the solarized glass converter plates. The extra cost is well worth the fidelity of the image in applications where accuracy of the beam profile is important. This especially true if the goal is to measure Top Hat uniformity.

Our unmounted UV conversion materials include:

Doped YAG Crystal (Green Florescence) products
20mm Round & 30mm Round, SUMITA Conversion Crystal.

P/N SPF01177 – 20mm Diameter UV Imaging conversion plate. For customers that have own imaging system. Converts UV image to visible for beam intensities 50μJ/ cm2 to 10mJ/cm2.

P/N SPF01150 – 30mm Diameter UV Imaging conversion plate - For customers that have own imaging system. Converts UV image to visible for beam intensities 50μJ/ cm2 to 10mJ/cm2.

Solarized Glass (Blue Florescence) products
50mm x 50mm, and 100mm x 100mm Rectangular, Solarized Glass Plates.

P/N SP90082 – 50mm x 50mm UV conversion plate – not suitable for <200nm wavelengths. For customers that have own imaging system. Converts UV image to visible for beam intensities 1mJ/cm2 to 20mJ/cm2. Not suitable for 193nm.

P/N SP90083 – 100mm x 100mm UV conversion plate – not suitable for <200nm wavelengths. For customers that have their own imaging system. Converts UV image to visible for beam intensities 1mJ/cm2 to 20mJ/cm2. Not suitable for 193nm.

Reimaging UV Laser Beam Profiling

Summary
Ophir-Spiricon offers three families of UV converter products for the indirect measurement of UV laser beam profiles:

  • C-mount turnkey systems: 4x reduction, 1:1 and 4x expansion
    • Highest cost, ease of use, high performance
  • Doped YAG crystal converter plates for use with imaging systems, CCTV lens.
    • Mid cost, mid to high performance
  • Solarized glass converter plates for use with imaging systems, CCTV lens.
    • Low cost, low performance

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