Spinning-disc interferometry (SDI) is a high-speed laser scanning approach to surface metrology that uses common-path interferometry to measure protein spots on a BioCD disk. The measurement sensitivity depends on the scanning pitch and on the time-base. Based on high-resolution laser scanning images of printed antibody spots, we quantify the protein sensitivity as a function of the scan parame...

Diode lasers are becoming increasingly important in length metrology. We demonstrate construction of a simple single-frequency diode laser 632,8 nm, used as a frequency standard in the laser interferometers. We present two different systems applied for frequency stabilization of diode laser . For diode laser used as the secondary standard, the system stabilizes diode temperature, the frequency ...

Sound can be described as the propagation of pressure variations in compressible media that involves compression and expansion and induces a change in the density of the medium. This change in acoustic pressure as it induces a change of the refractive index can be measured by optical methods, the most recent being the optical feedback interferometry. With this technique, a laser diode is beamin...

We describe a soft-x-ray laser interferometry technique that allows two-dimensional diagnosis of plasma electron density with picosecond time resolution. It consists of the combination of a robust high-throughput amplitude-division interferometer and a 14.7-nm transient-inversion soft-x-ray laser that produces approximately 5-ps pulses. Because of its picosecond resolution and short-wavelength ...

We report on a frequency-comb-referenced absolute interferometer which instantly measures long distance by integrating multi-wavelength interferometry with direct synthetic wavelength interferometry. The reported interferometer utilizes four different wavelengths, simultaneously calibrated to the frequency comb of a femtosecond laser, to implement subwavelength distance measurement, while direc...

We report a dramatic improvement of the spatial coherence and beam divergence (0.66 mrad) of a 13.2 nm wavelength Ni-like Cd tabletop laser by injection seeding the soft x-ray laser amplifier with high-harmonics pulses generated in a Ne gas jet. This phase coherent laser is an attractive light source for at-wavelength interferometry of extreme ultraviolet lithography optics and other applications.

This paper describes the principle of precise length measurements using multi-wavelength interferometry. Three different examples are given in order to demonstrate PTB’s ability in this field: 1) Measurements of absolute distances up to 10 m performed by combination of the variable wavelength interferometry with fixed wavelength interferometry using two wavelengths simultaneously, 2) a three-wa...