Abstract
A two-dimensional, autocloned, photonic crystal is used to control the pulse duration of a sub-picosecond Ti:sapphire laser for material processing applications. The photonic crystal consists of a periodic stack of 99. 5-nm-thick Ta2O5 layers and 137.5-nm-thick SiO 2 layers with a periodic surface corrugation deposited on a SiO 2 substrate. The photonic crystal size is 10 × 10 mm 2. It can withstand intense sub-picosecond laser pulses. Photonic crystals behave as a negative group velocity dispersion (GVD) device in a low incidence angle range and also as a positive GVD device in a high incidence angle range. By simply changing the incidence angle of the laser, pulsewidth can be controlled. With a 200-fs up-chirped pulse, the transmitted pulsewidth is compressed down to 121 fs at an incidence angle of 10°. At an incidence angle of more than 20°, pulsewidth is steeply stretched mainly because of the reduction in transmission spectral band in the photonic crystal. A down-chirped 200-fs pulse is stretched up to 232 fs because of the negative OVD of the photonic crystal at a normal incidence, whereas at a high incidence angle of 54°, pulse is compressed down to 111 fs because of the positive GVD of the photonic crystal. An autocloned photonic crystal can be used as a very simple GVD device to control an intense sub-picosecond laser pulse.
Original language | English |
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Pages (from-to) | 2566-2571 |
Number of pages | 6 |
Journal | Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers |
Volume | 45 |
Issue number | 4 A |
DOIs | |
Publication status | Published - 2006 Apr 7 |
Externally published | Yes |
Keywords
- Group delay dispersion
- Optical pulse compression
- Photonic bandgap material
- Ultrafast process
ASJC Scopus subject areas
- Engineering(all)
- Physics and Astronomy(all)