Stress-induced waveguides in Nd:YAG by simultaneous double-beam irradiation with femtosecond pulses

• Published in: Optical materials Vol. 51; pp. 84 - 88
• Main Authors: Castillo, Gabriel R., Romero, Carolina, Lifante, Ginés, Jaque, Daniel, Chen, Feng, Varela, Óscar, García-García, Enrique, Méndez, Cruz, Camacho-López, Santiago, Vázquez de Aldana, Javier R.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.01.2016
• Subjects: Integrated optics devices; Laser materials processing; Waveguides channeled; Integrated optics devices; Laser materials processing; Waveguides channeled
• DOI: 10.1016/j.optmat.2015.11.025
• ISSN: 0925-3467

•High-performance waveguides are fabricated in Nd:YAG by femtosecond laser irradiation.•A novel setup based on double-beam (DB) irradiation is presented.•DB irradiation technique improves the symmetry and performance of stress-induced waveguides.•DB irradiation reduces the laser-induced damage of waveguides. We report on the fabrication of stress-induced waveguides in Nd:YAG (neodymium doped yttrium aluminum garnet, Nd:Y3Al5O12) by simultaneous double-beam irradiation with femtosecond laser pulses. An interferometer was used to generate two femtosecond laser beams that, focused with certain lateral separation inside the crystal, produced two parallel damage tracks with a single scan. The propagation of the mechanical waves simultaneously created in both focal spots produced a highly symmetrical stress field that is clearly revealed in micro-luminescence maps. The optical properties of the double-beam waveguides are studied and compared to those of single-beam irradiation, showing relevant differences. The creation of more symmetric stress patterns and a slight reduction of propagation losses are explained in terms of the fact that simultaneous inscription allows for a drastic reduction in the magnitude of “incubation” effects related to the existence of pre-damaged states.