Logo PTB


Division 4

Division 4 which is responsible for optics is home to three base units: that of length, time and luminous intensity. On this basis, standards and measuring methods of highest accuracy are developed for various optical quantities.



Division "Optics" supports industry, science and society by providing measurement services, research and development in the field of optical technology. Based on the SI units of length, time and luminous intensity different units are realized and disseminated. Further more, accurate standards and measurement techniques are developed.

The division realizes the time scale UTC (PTB), which is the legal time in the Federal Republic of Germany, performs precision measurements in different fields of optics and cooperates in international standardisation and certification.


We report on experimental results in a new regime of relativistic light-matter interaction employing midinfrared (3.9−μm wavelength) high-intensity femtosecond laser pulses. In the laser-generated plasma, electrons reach relativistic energies already for rather low intensities due to the fortunate λ2 scaling of the kinetic energy with the laser wavelength. The lower intensity efficiently suppresses optical field ionization and creation of the preplasma at the rising edge of the laser pulse, enabling an enhanced efficient vacuum heating of the plasma. The lower critical plasma density for long-wavelength radiation can be surmounted by using nanowires instead of flat targets. Numerical simulations, which are in a good agreement with experimental results, suggest that ≈80% of the incident laser energy has been absorbed resulting in a long-living, keV-temperature, high-charge-state plasma with a density more than 3 orders of magnitude...

[ more ]

Im Rahmen der engen Zusammenarbeit zwischen Fertigung (FB 5.5) und Messtechnik (FB 4.2) in der PTB sind hochgenaue Referenzflächen gefertigt worden, die sich aus Kugelflächen zusammensetzen. Durch Rückführung der Sphärizität wurden die Referenzflächen im Rahmen des EMPIR-Projektes 15SIB01 erstmalig zur Überprüfung eines Asphären- und Freiformflächenmessgerätes verwendet.

[ more ]
More news


Further InformationFurther Information