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:
| Outer Diameter: | 5 - 100 mm |
| Aperture Shape | Round, square, multi-aperture, other |
| Aperture Size | 10 um - 60 mm |
| Wavelength spectrum | 193 - 11000 nm, each element designed for single wavelength |
| Transfer Region | Small; sharp edges |
| SNR | ~500 |
| Shape size | >5 um |
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
| Part Number | Diameter (mm) | Aperture Size (um) | Aperture shape | Material |
| DM-002 | 11 | 65 | Square | Fused Silica |
| DM-003 | 11 | 165 | Square | Fused Silica |
| DM-004 | 25.4 | 1750 | Square | Fused Silica |
| DM-005 | 25.4 | 3500 | Square | Fused Silica |
| DM-006 | 25.4 | 7000 | Square | Fused Silica |
| DM-007 | 25.4 | 10838 | Round | Fused Silica |
| DM-008 | 20 | 8428 | Round | Fused Silica |
| DM-009 | 25.4 | 6200 | Round | Fused Silica |
| DM-010 | 25.4 | 5680 | Round | Fused Silica |
| DM-011 | 11 | 4817 | Round | Fused Silica |
| DM-012 | 11 | 3612 | Round | Fused Silica |
| DM-013 | 11 | 2408 | Round | Fused Silica |
| DM-014 | 11 | 4214.9 | Round | Fused Silica |
| DM-015 | 11 | 3000 | Round | Fused Silica |
| DM-016 | 11 | 5400 | Round | Fused Silica |
| DM-017 | 85 | 50075 | Square | Fused Silica |
| DM-019 | 25.4 | 300 | Square | Fused Silica |
For a quotation of an above Part Number, please specify the wavelength used.
Contact Us for more information or for a custom solution.
