In this paper, we report our recent research progresses on the design, fabrication and characterization of photonic sensors for harsh environment applications, with the help of novel Integrated Additive and Subtractive Manufacturing (IASM) system. Glass 3D printing with direct laser melting process in this IASM system presents the dimension accuracy on the order of tens or hundreds of microns. The addition of laser micromachining allows the fabrication of structures with micron dimension accuracy, showing the unique advantage of IASM system in high dimensional accuracy compared with traditional 3D printing process. A number of photonic sensors and devices will be summarized and presented, including (1) 3D printed all-glass fiber-optic pressure sensor for high temperature applications, (2) Information integrated glass module fabricated by IASM and (3) IASM for microfluidic pressure sensor fabrication.
We report a prototype reflection-mode fiber optic probe based on quantum dots filled micro-cavity. The probe was fabricated by sealing quantum dots liquid or coating inside a glass capillary pigtailed with a multimode optical fiber. And the probe was tested for in situ measurement of temperature change. By analyzing the back-reflected fluorescence signals generated from the quantum dots, the localized temperature of the microcavity structure could be correlated. The sensitivities based on fluorescence peak wavelength and full-width at half-maximum (FWHM) were calculated for both sensors in the biologically meaningful temperature range of 33.0-42.0C. This proposed reflection-mode trumpet-shape micro-cavity probe is attractive for chemical and biological sensing because it is cost-effective, simple to fabricate, mechanically robust and miniaturized in size.
In this paper, we summarize our recent research progresses on the understanding, design, fabrication, characterization of various photonic sensors for energy, defense, environmental, biomedical and industry applications. Femtosecond laser processing/ablation of various glass materials (fused silica, doped silica, sapphire, etc.) will be discussed towards the goal of one-step fabrication of novel photonic sensors and new enabling photonic devices. A number of new photonic devices and sensors will be presented.
Optofluid system has been more and more attractive in optical sensing applications such as chemical and biological analysis as it incorporates the unique features from both integrated optics and microfluidics. In recent years, various optofluid based structures have been investigated in/on an optical fiber platform which is referred to as “lab in/on a fiber”. Among those integrated structures, femto-second laser micromaching technique plays an important role due to its high precision fabrication, flexible design, 3D capability, and compatible with other methods. Here we present a ferrofluid based optical fiber magnetic field sensor fabricated by femtosecond (fs) laser irradiation .With the help of fs laser micromaching technique, a micro-reservoir made by capillary tube assembled in a single mode optical fiber could be fabricated. The micro-reservoir functions as a fiber inline Fabry-Perot (FP) cavity which is filled by ferrofluid liquid. The refractive index of the ferrofluid varies as the surrounding magnetic field strength changes, which can be optically probed by the FP interferometer. A fringe visibility of up to 30 dB can be achieved with a detection limit of around 0.4 Gausses. Due to the fabrication, micro-reservoirs can be assembled with optical fiber and distinguished through a microwave-photonic interrogation system. A quasi-distributed magnetic field sensing application has been demonstrated with a high spatial resolution of around 10 cm.