HP Series (High Gas Pressure)
The ‘HP’ series of lenses was designed to allow the use of standard, relatively thin focusing lenses
in high assist gas pressure applications. The principle of operation is that the lens assembly is sealed
with a pressure window and ‘O’ ring behind the lens. Gas is allowed into the space between the lens
and pressure window through a hole in the mounting cell and via a specially designed internal spacer.
By its use in the parallel laser beam, the pressure window does not contribute additional spherical
aberration. ‘HP’ series lenses are useful where backspatter occurs and lenses are regularly replaced.
The thinner standard lenses are, of course, less expensive to replace than a thick lens element which
requires more costly ZnSe in its manufacture. All ‘HP’ series lenses are for use at 10.6μm.
Clear aperture : 25.4mm.
Lens material/window material : Laser grade ZnSe.
Coatings : Low absorption anti-reflection coated all surfaces.
Sealing : By means of ‘Viton’ O ring.
Cell material : Aluminium HE30.
Finish : Black anodised.
Cell size : M11 type (see Fig 26.11).
Pressure window : 28mm dia x 5mm thick.
Maximum gas pressure : 25 bar.
The pressure window is replacement P/No. 11ZWA50. The ‘O’ ring is type BS022.
The ‘HP’ series lenses can be used with any of the following equipment:
FF25 and CFF25 focusing heads (Section 63.0)
WMA water cooling mount (Section 20.3)
HGNA high pressure nozzle (Section 22.0)
ZX10 zoom beam reducer (Section 24.11)
SNA Gas Nozzle (Section 9.10)