Formation of planar waveguides in bismuth germanate by⁴He⁺ion implantation

Abstract

Planar optical waveguides have been formed in crystalline bismuth germanate (BGO) Bi4Ge3O12, by He+ ion implantation. The refractive index profiles have been determined using a dark-mode technique at 0.6328 and 0.488 mu m. In the region of the electronic and nuclear stopping power of the ion beam in BGO there is an index enhancement, which forms an optical 'well'. This is stable up to approximately 200 degrees C, but then there is a gradual recovery of index up to 400 degrees C. Between 425 and 450 degrees C, for heavily implanted samples (>or=4*1016 ions/cm2), the well rapidly disappears, and is replaced by a sharp 'barrier' of reduced index. For lower dose implants (<4*1016 ion/cm2) at 450 degrees C many of the modes disappear without being replaced by a sharp barrier.

Formation of slab waveguides in eulytine type BGO and CaF2 crystals by implantation of MeV nitrogen ions

“…It has high electro-optic coefficients (3.3 pm/V for Bi 12 GeO 20 ), making it useful in nonlinear optics for building Pockels cells, and can also be used for photorefractive devices. Formation of planar waveguides in Bi 4 Ge 3 O 12 (eulytine) crystals by implantation of He + ions of the 1-2 MeV energy range was first reported by Mahdavi et al [13]. Here we present our preliminary results in fabricating slab waveguides in eulytine type bismuth germanate crystals using a medium-sized ion, N + , instead of the light ions used in the above mentioned works.…”

Optical properties of crystalline and ion-beam amorphized Bi12GeO20: Relevance for waveguide applications

“…For instance, it can be used in applications as diverse as doping silicon wafers [11], introducing metallic nanoclusters in a dielectric matrix [12] or fabricating optical waveguides [13][14][15][16]. A few experiments have been performed so far on the eulytine structure of BGO by using light ions such as He [17] or N [18,19] and high fluences. A clear rise in refractive index has been obtained leading to good quality waveguides.…”

Femtosecond-laser micromachined optical waveguides in Bi4Ge3O12 crystals

“…The features of BGO crystal, such as its nonhygroscopic nature, its high electro-optic coefficient, and its easy preparation, make it an ideal crystal for nuclear physics, space physics, nuclear medicine, high-energy physics, and other fields. In early works, BGO waveguides were fabricated by ion implantation and swift ion irradiation [28][29][30][31], and the guiding characteristic and the effect of the annealing treatment were investigated. Fs-laser micromachining was utilized to fabricate waveguides in BGO crystal with a dual-line approach [32].…”