Product Code: ICA10_M1005

Picosecond Laser-Induced Color Centers in Glass Optics
Authors:
David Ashkenasi, Laser- and Medical- Technology Berlin GmbH (LMTB), Applied Laser Technology; Berlin Germany
Andreas Lemke, Laser- and Medizin-Technologie Berlin Gmbh (LMTB), Applied Laser Technology; Berlin Germany
Presented at ICALEO 2010

It is known that ionizing radiation (X-ray, gamma rays, electrons) can induce numerous changes in the physical properties of glasses. The most obvious effect is visible coloration, which is caused by the accumulation of color centres (defects) in the irradiated volume. The application of these induced colour centres has prompted a renewed interest since these can be generated and bleached reversibly. In this contribution results on laser induced colour centres in different types of glasses using picosecond laser pulses are presented. For example, an unexpectedly low peak power threshold of < 0.2 MW for the laser induced coloring in a BK7 glass substrate is observed at a wavelength of 355 nm and a pulse width of 6 ps. For soda-lime glass, the threshold is even a factor 2 lower. In addition, picosecond laser pulses even at a longer wavelength of 532 nm and even 1064 nm induce color centres in many different glasses. By applying different focussing optics the influence of changing focal length and energy flux density on the volume colouring effect have been analysed. Transmission changes, non-linear optical effects and possible implications for guiding optics are presented.