Pole®
Louisenthal (Germany)
Type: Covert security thread add-on — polarisation filter-detectable hidden design embedded within optically variable security threads, providing a covert Level 2 authentication layer
Overview
Pole® is a Louisenthal proprietary covert security technology for banknote security threads, introduced in 2005. It is not a standalone security feature but an add-on layer integrated within existing Louisenthal optically variable threads — principally the ColorShift™ family — adding a hidden polarisation-detectable element that is completely invisible under normal viewing conditions. Pole represents an innovative and attractive security element developed by G+D/Louisenthal to supplement or replace widely used ultraviolet fluorescence.
Pole® was an early IACA award winner: the Pole® polarisation feature for optically variable security threads was introduced back in 2005 and has since been incorporated into Kazakhstan's new 1000 Tenge banknote, as well as the current series of Czech and Bulgarian banknotes.
Technology & Effects
Pole® exploits the polarising properties of certain optically variable thin-film materials within the thread structure. Under normal ambient illumination — whether reflected or transmitted — Pole® is entirely invisible: the thread presents only its standard overt appearance (colour shift, clear text, etc.) with no indication that any additional element is present. When a polarising filter is placed over the thread and rotated, a hidden design or pattern becomes visible that is otherwise completely concealed. This polarisation-dependent visibility is achievable only with the specific thin-film architecture used in Louisenthal's thread production; commercially available polarising filters used over a counterfeited thread would reveal nothing, as the necessary optical microstructure in the film would be absent.
The ColourShift thread can be combined with various covert security features, including covert information for polarization filters (Pole). The hidden polarisation pattern can carry denomination-specific designs, national symbols, text, or geometric elements — all defined at the time of thread origination and unique to each central bank customer's specification. The design revealed under a polarising filter is typically not disclosed publicly, reinforcing its value as a covert teller and specialist authentication tool.
On the Kazakhstan 1000 Tenge OSCE commemorative banknote, the ColourShift/ColorFix window thread incorporates MultiCode™ and Pole® features. With the aid of a polarising filter, a further hidden design is visible.
Form Factors & Application
Pole® is applied during thread production at Louisenthal's manufacturing facilities, integrated within the thin-film layer structure of the optically variable thread. It is available as an add-on to ColorShift™ threads and in principle to other Louisenthal thread products that use appropriate thin-film layers. The thread's physical dimensions, embedding behaviour in paper, and overt visual appearance are unchanged by the addition of Pole® — the polarisation-detectable content is entirely invisible in all standard observation modes. The hidden design is revealed only when a specialist polarising filter is placed over the windowed area of the thread and rotated to the appropriate orientation.
Security Levels
Pole® operates at Level 2. Detection requires a polarising filter — a simple, low-cost device available to bank tellers, cash handling centres, and law enforcement — but one that is not available to the general public in the normal cash transaction context, and that provides a clear positive/negative authentication signal. Unlike UV fluorescence, which is widely known and can be simulated by commercially available UV-fluorescent inks, the polarisation response requires the specific thin-film microstructure of a genuine Louisenthal thread, making simulation with commercial materials essentially impossible. This positions Pole® as a more robust Level 2 element than UV fluorescence, which is reflected in Louisenthal/G+D's positioning of it as a supplement or replacement for UV.
Notable Deployments
Pole® has been incorporated into Kazakhstan's 1000 Tenge banknote, as well as the Czech and Bulgarian banknote series. All three deployments combine Pole® with ColorShift™/ColorFix threads from Louisenthal, illustrating its role as an add-on covert layer within the same thread that delivers the primary overt colour-shift authentication.
- Name
- Pole®
- Category
- Security Feature
- Effect Types
- Machine readable other
- Company
- Product Page
- View on Supplier Site
- Linked Features
- 1 security feature