ZnSe Scanning Lenses, 48 TSL Series
48TSL scanner lenses specially designed and optimized for use in CO2 laser 2-axis galvo-scanner
systems with full beam diameters of up to 15.0mm.
Mirror sets appropriate for use with beam diameters up to 15mm require an increase in mirror
separation in comparison with smaller mirrors. These changed optical conditions are catered-for
by the 48TSL series.
These single-element lenses are designed to represent the best achievable compromise for on-axis
and off-axis aberrations, field flatness and F-theta characteristics, obtainable using single-element
spherical-surface designs of (standard) 48mm diameter.
See Table 10.121 and Figure 10.122.
Material, coatings and quality.
ULO Optics use only full specification ‘lasergrade’ ZnSe raw material. The lenses are polished
to surface accuracies of better than 1/50th wave spherical accuracy and 1/400th wave ovality as determined
over the specified beam diameter. Surface roughness is better than 2nm (RMS), and centration to
better than 0.05mm ETV. The lenses are anti-reflection coated with ultra-low absorption thin films
giving a reflectivity of less than 0.25% per surface (as measured at normal incidence).
Notes on table 10.121
(1) Focused spot diameters are
based on an incident 15mm full
beam diameter (11.8mm 1/e2)
and TEM00 mode.
(2) The ‘average’ is the mean
from 25 field positions.
(3) Each scanning mirror deflects
the beam by up to 20º from the
(1) The lenses are meniscus form; one concave and one convex surface.
(2) The concave always faces the incident beam.
(3) For all TSL lenses, the diameter is 48.0 +0/-0.1 mm, and the edge thickness is 3.0 +/-0.1 mm.
(4) X scanning mirror is 34.8mm from the edge of the first (concave) surface and the Y scanning mirror
is 17.7mm from the edge of the first (concave) surface. Any 48TSL lens can therefore replace any other
in the lens cell and be correctly positioned.
(5) The lenses give the smallest possible spot diameters for a single element with the given mirror
locations and incident beam diameter.