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Ultra-Long™ Phase Mask

150 mm long aperture
Longest holographically recorded phase mask available

With a length of 150 mm, the Ultra-Long™ Phase Mask is the longest such device available in the world. It is holographically recorded, eliminating "stitching errors" that are a cause of side lobes.

Typical FBG applications:

Dispersion compensation gratings (DCGs)
Dense wavelength division multiplexing (DWDM)
Narrow band filters

Technical Specifications

Operating wavelength:	190 - 320 nm

Phase mask period:	0.6 - 1.2 μm

Period manufacturing tolerance:	± 0.3 nm for unchirped masks (± 0.1 nm optional)

Period measurement accuracy:	± 0.02 nm

Dimensions	Substrate size / Aperture 15.0 mm X 158.75 mm / 10 mm X 150 mm

Chirp range (for chirped masks)	0.03 nm/cm - 30 nm/cm

Diffraction efficiency	≤ 5 % in 0th order; ≥ 30 % in ± 1st order

Damage threshold	Better than 1 J/cm2 per pulse at 50 Hz @ 248 nm

Material	Synthetic fused silica

Substrate flatness	< 2 µm TIR, both sides

AR coating	Optional

Wedge	< 30 arcsec

Thickness	3.2 mm ±0.1 mm


For chirped masks; center period precision ± 0.5 nm with ± 200 μm center positioning error

Ordering Information

ULPM (ULPMC if chirped) - {wavelength of laser} - {mask period} - {mask dimension}

Example: an Ultra-Long phase mask to be used with a KrF excimer laser at 248 nm with a period of 1.0600 μm is specified as:
ULPM - 248 - 1.0600 - 158.75

Example for 0.083 nm/cm chirped mask:
ULPMC - 248 - 1.0600 - 158.75 - 0.083 nm/cm