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Q: Fachverband Quantenoptik und Photonik

Q 34: Ultrashort Laser Pulses: Applications II

Q 34.3: Vortrag

Mittwoch, 10. März 2010, 14:30–14:45, F 342

Ultrashort-pulsed, ultra-broadband nondiffracting tubular beam generated with a phase only spatial light modulator — •Martin Bock and Ruediger Grunwald — Max Born Institute, Max-Born-Straße 2a, 12489 Berlin, Germany

Tubular beams propagating diffractionless were generated with a high-resolution liquid crystal on silicon spatial light modulator (LCoS-SLM). Contrary to higher-order Laguerre-Gauss or Bessel-Gauss modes [1,2], such beams exhibit no significant extrinsic orbital angular momentum. The new approach is based on generating adapted angular distributions by shaping the beam with a bi-prism bent to an annulus (torus-axicon) which was programmed into the SLM. The active area was completely involved by including a convex conical center thus leading to high energy efficiency. A diverging wave from the center is superimposed with a converging wave from the outer parts. In the experiments we used a Ti:sapphire oscillator emitting 10 fs pulses to illuminate the SLM. The ring-shaped wavepacket resulting from the interference of the parts constituting the wave was found to propagate in the fashion of a nondiffracting beam. With 20 fs, the pulse duration was only slightly changed. We suppose that this was mainly caused by the cover glass of the SLM.

[1] D. McGloin, et al., Opt. Comm. 225, 215-222 (2003).

[2] I. G. Mariyenko, Opt. Express 13, 7599-7608 (2005).