Polarisation filters suit laser applications

The range includes polarising bandpass filters, which combine an efficient polariser and bandpass filter in a single optical component.

These filters combine the best attributes of other optical polariser technologies with the laser clean-up properties of a state-of-the-art bandpass filter.

Semrock said that its polarisers have a contrast ratio guaranteed to exceed 1,000,000-to-1 (extinction ratio <10-6).

At the same time, the bandpass characteristics include transmission greater than 93 per cent with steep edges and high out-of-band blocking.

The optical quality of Semrock's ion-beam sputtered thin film technology offers minimal scatter, wavefront distortion and beam deviation to satisfy even the most demanding imaging applications.

These optical components come standard with a large 22mm aperture size (larger is available) and feature the convenience of 90deg beamsplitter functionality.

All filters have the hard-coated reliability (with a five-year warranty) and the high laser damage threshold (>1J/cm2).

'These polarising bandpass filters are excellent laser source clean-up filters to eliminate the undesired polarisation at the laser line and light noise away from the laser wavelength, as well as detection filters to pass a laser wavelength range and block background noise,' said Semrock president Dr Victor Mizrahi.

They are suitable for a wide variety of laboratory laser applications, especially those involving holographic and interferometric systems, as well as laser materials processing, polarisation diversity detection in communications and range finding, and fluorescence polarisation and second-harmonic-generation imaging.

Semrock's polarisation filters are available for same-day delivery for the 405nm, 532nm and 635nm laser wavelengths, with additional wavelength ranges and new types of filters launching in the coming months.

Semrock has also developed opto-mechanical mounts designed for conveniently mounting the stock beamsplitter filters in standard rotation stages while accessing the full 22mm clear aperture.