The University of Southampton

New ultrafast optical phenomenon challenges a common belief in optics

Published: 11 January 2008

Researchers at the ORC in collaboration with the University of Joensuu, Finland, have presented the first evidence of non-reciprocal photosensitivity, revealing a new property of interaction of light with matter which could have a significant impact on optical data storage, laser machining and surgery.

This new optical phenomenon is reported in the current advance online publication of Nature Photonics (13 January 2008).

Photosensitivity, the term given to describe an object’s response to light, is a material property which is relevant to many phenomena and applications, from photosynthesis and photography to optical data storage and ultrafast laser writing. 

Until now, it has been a common belief that, in a homogenous medium, if you reverse the direction of the light transmitted, photosensitivity and the corresponding light-induced material modifications do not change. However, our researchers used a non- centrosymmetric material and have discovered that a single intense beam of a femtosecond laser interacts with the crystal differently for opposite directions of light transmission.

The group also observed a mirror image in the structural modifications when the propagation direction of the writing beam was reversed as illustrated in the image. 

‘These results are significant and we anticipate that non-reciprocity of ultrafast laser writing could lead to new opportunities in material processing, optical manipulation and data storage,’ comments Professor Peter Kazansky. ‘Here at the ORC we have the facilities and expertise to make these opportunities a reality.’ 


1. The paper is entitled W. Yang, P.G. Kazansky, Y.P. Svirko, ‘Non-reciprocal ultrafast laser writing’. The work was supported by the EPSRC and was undertaken by the Physical Optics Group at the ORC. To read more about the work of this group visit

2. The Optoelectronics Research Centre at the University of Southampton is one of the largest university-based research groups entirely devoted to optoelectronics in the world, and has maintained a position at the forefront of photonics research for over four decades. Its long and well established track record in the fields of optical fibre, lasers, waveguides, devices and optoelectronic materials has fostered innovation, enterprise, cross-boundary and multi-disciplinary activities. It has built strong links with industry, research institutions and universities around the world, from informal collaborations to large-scale funding. Several spin out companies, including Southampton Photonics Inc, Stratophase Ltd, Mesophotonics Ltd and ChG Southampton Ltd, have commericalized the fruits of ORC research; while its extensive outreach programme has brought lasers and optical fibres into schools across the country.

Further information

Professor Peter Kazansky, Optoelectronics Research Centre, tel: +44 (0)23 8059 3083, email

Marketing Officer, Optoelectronics Research Centre, tel: +44 (0)23 8059 3877, email: 

Posted by Marketing Officer, on 14 January 2008

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