Introduction
HOLO/OR has developed a series of projection masks to answer the demand of using such masks with very high powered laser sources in the UV-VIS spectrum. These masks have two different forms: the dielectric mask has a reflective coating that blocks unwanted light, and the transmissive mask uses a diffractive pattern that diffuses this unwanted light at large angles.
Typical Parameters:
Dielectric Reflective Mask
Dielectric masks are Fused Silica substrates patterned by very thin (~1um) reflective coating. The coated part reflects the incoming beam while the uncoated part transmits the beam.
Typical Applications:
- Micro patterns projection for high power systems
- UV lithography
Schematic sketch of the optical system:
Fig 1. Typical Set Up
HOLO/OR can design and manufacture a custom dielectric mask to match the customer’s needs.
Fig 2.Real measurement of custom Dielectric Mask taken with microscope magnification
Features of Dielectric Mask:
- High damage threshold
- Low absorption
- High reflection (>99%) in reflective part
- High transmission (>95%) in transparent part
- Very thin dielectric reflective layer (~1 um)
Transmissive Imaging Mask
Principle of operation:
The Transmissive Mask transmits all incident illumination without any blocking. The pattern to be imaged is a clear mask area that transfers the light without interruption, while the surrounding areas transfer light through a specially designed diffractive pattern which diffuses light in large angles. Placed close to the focal plane of a focusing lens, a pinhole blocks most of the diffused light, so that a high-contrast intensity shape is achieved at the image plane.
Schematic sketch of the optical system:
Features of Transmissive mask:
- No danger of reflected light causing damage to optical system
- ~100% transmission
- Higher laser damage threshold than for reflective mask
- Affordable price, similar to that of other diffractive elements
Transmissive Mask element
Measured Intensity
Standard products
For a quotation of an above Part Number, please specify the wavelength used.
Contact Us for more information or for a custom solution.
