Ultrafast-laser-written glass polarization converter inexpensively creates optical vortices

Ultrafast-laser-written glass polarization converter inexpensively creates optical vortices

Southampton, England--Glass optical elements with vortex-shaped nanogratings developed by scientists at the University of Southampton's Optoelectronics Research Centre (ORC) can change a laser beam by creating optical vortices--a property valuable for superresolution optics and optical manipulation, among other applications.1

The prototype optical vortex converter, which works at a 532 nm wavelength, takes incident circularly polarized light and converts it to radially or azimuthally polarized light, depending on whether the incident light has left- or right-handed circular polarization; other polarization tricks are also possible. Azimuthally polarized light can be used at a focus to create a ring-shaped particle trap.

Fabrication by direct laser writing
The monolithic space-variant polarization converters are fabricated by direct writing with 270 fs pulses of light at a 1030 nm wavelength from a femtosecond laser, which spontaneously forms nanogratings in the glass with directions that are based on the polarization of the ultrafast beam. THe gratings take the form of spiraling lines formed by strings of nanovoxels (volumetric nanopixels).

Previous research at the ORC showed that lasers with fixed polarization produce voxels consisting of a periodic arrangement of ultrathin (tens of nanometers) planes. By passing polarized light through such a voxel imprinted in silica glass, the researchers observed that it travels differently depending on the polarization orientation of the light. This "form birefringence" phenomenon is the basis of the new polarization converter. The advantage of this fabrication approach over existing methods for microscopy is that it is 20 times cheaper and it is compact.

"Before this we had to use a spatial light modulator based on liquid crystal which cost about £20,000," said Peter Kazansky, one of the researchers. "Instead we have just put a tiny device into the optical beam and we get the same result."

The researchers have also developed and adapted this technology for five-dimensional optical recording. "We have improved the quality and fabrication time and we have developed this five-dimensional memory, which means that data can be stored on the glass and last forever," said Martynas Beresna, lead researcher for the project. "No one has ever done this before." The researchers are working with the Lithuanian company Altechna to introduce this technology to the market.


1. Martynas Beresna et al., Applied Physics Letters 98, 201101 (2011).

Most Popular Articles


Handheld Spectrometers

Spectroscopy can be a powerful measurement tool, and handheld spectrometers offer the ultimate in portability, so the instrument can be applied wherever meas...

Fracking, climate change, and lasers:  new tools to reduce fugitive methane emissions

This webcast, sponsored by Hamamatsu Corporation, covers recent developments and field deployments of compact quantum-cascade-laser (QCL)-based methane senso...

Opportunities in the Mid-IR

The technology for exploiting the mid-IR is developing rapidly:  it includes quantum-cascade lasers and other sources, spectroscopic instruments of many...

Fiber Optic Sensors – Fundamentals, Principles and Applications

In this webcast, sponsored by Nufern, we focus on optical fiber sensing technology.  Fundamental concepts will be presented first, followed by the under...
Technical Digests

Keeping pace with developments in Raman spectroscopy for molecular and nanoparticle research

For demanding or custom spectroscopy solutions, care must be taken in selecting and integrating a...
Sponsored by

HIGH-POWER FIBER LASERS: Working in the kilowatt regime

High-power materials-processing fiber lasers are available in an increasing variety of forms, as ...
Sponsored by

Click here to have your products listed in the Laser Focus World Buyers Guide.


Phantom ir300

The Phantom ir300 provides extended spectral response beyond visible light spectrum up ...

Phantom Miro Family

The Phantom Miro family are small, lightweight digital high-speed cameras.

Miro Airborne

Miro Airborne is a high-speed camera designed for airborne applications.


Photonics Bretagne

Offers a cluster composed of research centers, schools and companies all in the field o...

Raw Communications

Provider of marketing services in the fiber optic data communications industry includin...

XiO Photonics B V

Offers strong competence in integrated optical products for visible light applications....
Social Activity
Copyright © 2007-2014. PennWell Corporation, Tulsa, OK. All Rights Reserved.PRIVACY POLICY | TERMS AND CONDITIONS