Optical lattice-like cladding waveguides by direct laser writing: fabrication, luminescence, and lasing

Abstract

We report on the fabrication of optical lattice-like waveguide structures in an Nd:YAP laser crystal by using direct femtosecond laser writing. With periodically arrayed laser-induced tracks, the waveguiding cores can be located in either the regions between the neighbored tracks or the central zone surrounded by a number of tracks as outer cladding. The polarization of the femtosecond laser pulses for the inscription has been found to play a critical role in the anisotropic guiding behaviors of the structures. The confocal photoluminescence investigations reveal different stress-induced modifications of the structures inscribed by different polarization of the femtosecond laser beam, which are considered to be responsible for the refractive index changes of the structures. Under optical pump at 808 nm, efficient waveguide lasing at ∼1 μm wavelength has been realized from the optical lattice-like structure, which exhibits potential applications as novel miniature light sources.

Mid-infrared channel waveguides in RbPb 2 Cl 5 crystal inscribed by femtosecond laser pulses

“…Unexploited possibility in this connection is optimization of the polarization orientation relative crystallographic axes, as RPC crystal belongs to the monoclinic class, and it is expected that it posses strong anisotropy. The basis for this view is the strong dependence of the waveguide propagation loss on the direction of writing beam polarization in the orthorhombic YAP crystal [18].…”

Stress-induced optical waveguides written by an ultrafast laser in Nd3+, Y3+ co-doped SrF2 crystals

“…On the contrary, the stress-induced birefringent waveguides (no nanogratings) are observed in bulk transparent materials, which is arisen by the coupling of elasto-optical and the mechanical stress induced at vicinity of the laser track [1][2][3][4][5][6]26]. Noticeably, the high symmetric fabricated type-II waveguides inside materials can preserve non-destructive material properties and high resistance by so called "double line" technique [7][8][9]. This direct writing gives rise to high index parallel lines as a core that can be fenced by low index strained lines (i.e., it is commonly known as depressed cladding waveguides) [9].…”

“…Noticeably, the high symmetric fabricated type-II waveguides inside materials can preserve non-destructive material properties and high resistance by so called "double line" technique [7][8][9]. This direct writing gives rise to high index parallel lines as a core that can be fenced by low index strained lines (i.e., it is commonly known as depressed cladding waveguides) [9]. In fact, there are coexisting of different phases in written waveguides inevitable to allow wide tunability in the refractive index contrast [9].…”

“…This direct writing gives rise to high index parallel lines as a core that can be fenced by low index strained lines (i.e., it is commonly known as depressed cladding waveguides) [9]. In fact, there are coexisting of different phases in written waveguides inevitable to allow wide tunability in the refractive index contrast [9]. This can facilitate light confinement and guiding structure accompanied by micro-and sub-micron dimension inside bulk materials becoming one of the key building blocks in photonic devices.…”

“…To improve the communication bottleneck and waveguide lasers in Nd 3+ doped disordered crystals relative to Nd 3+ doped transparent glass and crystals with unique properties of high thermal conductivity, inhomogeneous broadening and large stimulated emission cross-section [7][8][9][10][11]. In particular, the SrF 2 crystal is multifunctional optical raw material and could be widely disseminated in many fields.…”