A monolithic micro-tensile tester for investigating silica micromechanics, fabricated and fully operated using a femtosecond laser

We report on the use of femtosecond laser for fabricating, loading and in-situ measuring using third-harmonic signal generation a micro-tensile tester for characterizing silica and its polymorphic phases

Ultrafast laser processing of glass for MEMS and micro-fluidic applications

An ultrafast laser processing of glass for MEMS and micro-fluidic application was presented in this paper. A low energy pulse, with an average power of 250 mW was used to write in the bulk microdevice contour along with the optical functions. The nature of the structural changes such as thermal conductivity changes was discussed in this paper from the view-point of laser processing of microdevices. New developments toward the integration of additional functionalities using ultra-fast laser exposure were also reviewed

Direct-write diffracting tubular optical components using femtosecond lasers

Over the last decade, femtosecond lasers have been used extensively for the fabrication of optical elements via direct writing and in combination with chemical etching. These processes have been an enabling technology for manufacturing a variety of devices such as waveguides, fluidic channels, and mechanical components. Here, we present high quality micro-scale optical components buried inside various glass substrates such as soda-lime glass or fused silica. These components consist of high-precision, simple patterns with tubular shapes. Typical diameters range from a few microns to one hundred microns. With the aid of high-bandwidth, high acceleration flexure stages, we achieve highly symmetric pattern geometries, which are particularly important for achieving homogeneous stress distribution within the substrate. We model the optical properties of these structures using beam propagation simulation techniques and experimentally demonstrate that such components can be used as cost-effective, low-numerical aperture lenses. Additionally, we investigate their capability for studying the stress-distribution induced by the laser-affected zones and possible related densification effects

Optofluidic lab-on-a-chip for rapid algae population screening

The rapid identification of algae species is not only of practical importance when monitoring unwanted adverse effects such as eutrophication, but also when assessing the water quality of watersheds. Here, we demonstrate a lab-on-a-chip that functions as a compact robust tool for the fast screening, real-time monitoring, and initial classification of algae. The water-algae sample, flowing in a microfluidic channel, is side-illuminated by an integrated subsurface waveguide. The waveguide is curved to improve the device sensitivity. The changes in the transmitted optical signal are monitored using a quadrant-cell photo-detector. The signal-wavelets from the different quadrants are used to qualitatively distinguish different families of algae. The channel and waveguide are fabricated out of a monolithic fused-silica substrate using a femtosecond laser-writing process combined with chemical etching. This proof-of-concept device paves the way for more elaborate femtosecond laser-based optofluidic micro-instruments incorporating waveguide networks designed for the real-time field analysis of cells and microorganisms

Arbitrary optical retardance patterns generated in bulk silica glass by laser-written stressors

We present micro-scale stressors written in bulk silica using an ultrafast laser. Stress from nanograting formation produces optical retardance, which is then tailored through control of the orientation, magnitude, and anisotropy of the stress field

On the anisotropy of stress-distribution induced in glasses and crystals by non-ablative femtosecond laser exposure

Femtosecond laser exposure in the non-ablative regime induces a variety of bulk structural modifications, in which anisotropy may depend on the polarization of the writing beam. In this work, we investigate the correlation between polarization state and stress anisotropy. In particular, we introduce a methodology that allows for rapid analysis and visualization of laser-induced stress anisotropy in glasses and crystals. Using radial and azimuthal polarization, we also demonstrate stress states that are nearly isotropic.Comment: 15 pages, 9 Figure

Formation of in-volume nanogratings with sub-100 nm periods in glass by femtosecond laser irradiation

We present direct experimental observation of the morphological evolution during the formation of nanogratings with sub-100-nm periods with the increasing number of pulses. Theoretical simulation shows that the constructive interference of the scattering light from original nanoplanes will create an intensity maximum located between the two adjacent nanoplanes, resulting in shortening of the nanograting period by half. The proposed mechanism enables explaining the formation of nanogratings with periods beyond that predicted by the nanoplasmonic model.Comment: 4 pages, 3 figure