Investigation of Femtosecond Laser-assisted Micromachining of Lithium Niobate

Abstract

Lithium Niobate has a potential for applications in electronics and communication industries due to its unique electro-optical, piezoelectric and nonlinear properties. Femtosecond laser machining offers the best alternative to machine the mechanically fragile and optically delicate lithium niobate crystal. This paper reports a study of the effect of femtosecond laser machining on the surface integrity of lithium niobate. The transmission electron microscopy reveals a 100nm thin amorphous region and a void. The chemical analysis shows a loss of lithium and oxygen from the surface and sub-surface. Optical illumination facilitates the selective readout of the written spots of 2 microns size.

Laser Micro-Machining of Spherical and Elliptical 3-D Objects Using Hole Area Modulation Method

“…Laser etching of silicon permits a wide variety of structures to be made since it is independent of the crystal plane orientation unlike wet etching. Various pulse lasers such as infrared Nd: YAG [11] and fs (Ti:Sapphire) lasers [10,15,16] have been used for machining of diamond and silicon [19] for a number of years. Similarly, crystal growth from the melt in the manufacture of silicon chips is followed by several processes of laser machining to obtain desired shape, size and other characteristics of silicon wafers.…”

“…Micro-engineering of products, devices and systems has been a growing field of research demanding new, innovative fabrication processes for nano/micro manufacturing of a wide range of materials [1]. Laser ablation or irradiation based micro-machining of basic geometric features on a variety of solid materials has been investigated by many researchers [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. Lasers are usually categorized as two groups: continuous wave (c.w.)…”

Good-Quality and High-Efficiency Dicing for Thick LiNbO3 Wafers Using Picosecond Laser Pulses

“…Ultrafast-laser material machining is promising in industrial products over conventional processing methods, without causing thermal damage. In order to improve processing precision and surface roughness, ultrafast laser machining in LiNbO 3 has been studied intensively in recent years [7][8][9][10][11][12]. Chen et al measured the surface-ablation threshold of LiNbO 3 , which decreases significantly along with an increase of the pulse number, until reaching a constant level due to an incubation effect [10].…”

Lithium Niobate Micromachining for the Fabrication of Microfluidic Droplet Generators

“…In fact, LN has been already employed for the realisation of pumping micro-systems [ 20 , 21 , 22 ], particles and fluid manipulation devices [ 23 , 24 , 25 , 26 , 27 ] and optical circuits [ 28 ]. Some preliminary studies on laser ablation of lithium niobate crystals were investigated to get periodic arrays [ 29 , 30 ], and, recently, even engraving microfluidic channels directly on lithium niobate were consequently reported in the literature by dicing [ 31 , 32 ] and by laser ablation [ 33 , 34 , 35 ]. In this paper, both laser ablation and dicing were investigated to engrave microfluidic channels on the surface of lithium niobate with the specific aim of defining the best micromachining conditions to reduce the material roughness within the microfluidic channels in order to host integrated optical waveguides facing their lateral walls.…”