FocusMonitor FM+

A scanning diagnostics system for the analysis of continuous wave laser beams

The FocusMonitor (FM+) is a scanning diagnostics system for the analysis of laser beam sources for laser material processing in laser beam welding, cutting as well as surface processing and others. 

FocursMonitor, FM+

The FocusMonitor measures the beam properties of focused laser beams. In addition to the geometric dimensions of the focused laser beam, the focus position in space, the beam parameter product as well as the beam quality factor M² are determined. The integrated z-axis enables the automatic measurement of complete caustics over up to four Rayleigh lengths.

The successful FocusMonitor has evolved into the FM+, providing new electronic features to meet the current and future demands of signal processing. A key part is a new main board with a 16 bit AD converter. The FM+ is operated with the new version of the PRIMES LaserDiagnosticsSoftware and is equipped with an Ethernet interface for fast and secure data exchange with computers or system controls. The FM+ can be mounted overhead without the need for additional hardware.

The Principle   

The FM+ is an opto-mechanically scanning diagnostics system. The laser beam is scanned using a specialized measuring tip. A small pin hole (typical diameter: 20 μm) in the measuring tip samples a small part of the laser beam. The sampled part of the laser beam is guided onto a detector element, which is chosen according to the power and wavelength of the laser radiation.

Hence, different laser beam sources and –systems can be measured at their maximum power simply by choosing the optimum measuring tip and detector. The high speed of the rotating measuring tip enables the analysis of high-power densities. Due to the high dynamic range of the employed analog digital converter, a very good signal-to-noise (S/N) ratio is achieved. High peak intensities as well as very low intensities are displayed precisely. This is one of the prerequisites for an automatic measurement of beam caustics in the focus range over at least four Rayleigh lengths according to ISO 11146. 

FocusMonitor FM+ HPD (High Power Densities)

The latest innovation in the FocusMonitor FM+ family. Through continuous development and the special design of the new measuring principle FS³ (Fused Silica Sensor System), it is now possible to measure and evaluate laser beams with very high-power densities of up to 50MW/cm2. Beam diameters of 100μm – 1200μm can be evaluated. The revolutionary design and the new functionality of the FocusMonitor FM+ HPD are available for beam sources in the wavelength range of 1.0 – 1.1μm.

With the FocusMonitor FM+ HPD, we present a milestone in the caustic analysis of laser beams in previously difficult to evaluate power ranges, which find use in cutting applications, for example.


Subject to change without notice.