Femtosecond laser micromachining of compound parabolic concentrator fiber tipped glucose sensors

Abstract

, "Femtosecond laser micromachining of compound parabolic concentrator fiber tipped glucose sensors," J. Biomed. Opt. Abstract. We report on highly accurate femtosecond (fs) laser micromachining of a compound parabolic concentrator (CPC) fiber tip on a polymer optical fiber (POF). The accuracy is reflected in an unprecedented correspondence between the numerically predicted and experimentally found improvement in fluorescence pickup efficiency of a Förster resonance energy transfer-based POF glucose sensor. A Zemax model of the CPC-tipped sensor predicts an optimal improvement of a factor of 3.96 compared to the sensor with a plane-cut fiber tip. The fs laser micromachined CPC tip showed an increase of a factor of 3.5, which is only 11.6% from the predicted value. Earlier state-of-the-art fabrication of the CPC-shaped tip by fiber tapering was of so poor quality that the actual improvement was 43% lower than the predicted improvement of the ideal CPC shape. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

Femtosecond Laser 3D Nano‐Printing for Functionalization of Optical Fiber Tips

“…Tens to hundreds of minutes <25 nm Fiber body (Silica)/ Metal (gold)/ Vacuum 2.5D High High (2016) [ 31] (2017) [ 32] Femtosecond laser ablation A few minutes 2 μm Fiber body(PMMA/PVDF/Silica) None 2.5D High High (2017) [ 34] (2021) [ 35] (2022) [ 33] Nanoimprint lithography (NL)…”

“…[ 20–24 ] However, the device's performance is limited due to its simple structure. In recent years, the precision and complexity of structures manufactured via advanced micro‐nano processing technology (detailed techniques are listed in Table 1 [ 25–46 ] ) have continuously improved, so that optical fiber tips have better performance and richer functions. Nevertheless, traditional micro‐nano processing technology usually requires complex and cumbersome processes and cannot achieve compatibility between high precision and real 3D, so further improvement is extremely difficult.…”

Polymer Optical Fiber Tip Mass Production Etch Mechanism to Achieve CPC Shape for Improved Biosensor Performance

“…This limitation can be overcome by increasing the numerical aperture of the fiber in order to collect more fluorescence. Although linear tapering of the fiber tip can increase the fiber numerical aperture, the maximum pickup efficiency is achieved using a nonlinear shape known as a Compound Parabolic Concentrator (CPC), as demonstrated in our previous work [16,18]. The CPC is a well-known profile that has been demonstrated for optimal light pickup efficiency [19] in various applications, such as increasing the light capture efficiency in solar energy systems [20] and improving the coupling of LED light into fibers [21].…”

“…In our previous work on POF-based glucose sensors, we manufactured POF Compound Parabolic Concentrator (POFCPC) tips using two different methods: (1) Heat-and-pull [4,16] and (2) Femtosecond (fs) laser micromachining [18]. The methods were characterized in terms of their improvement in light capturing efficiency compared to the conventional sensor with a plane-cut fiber tip, which Zemax modelling of an ideal CPC tip predicts to be a factor of η = 3.96 [16,18]. In the heat-and-pull method, a local area of the fiber is heated and pulled to parabolically taper it.…”

Reflection-Based Thin-Core Modal Interferometry Optical Fiber Functionalized With PAA-PBA/PVA for Glucose Detection Under Physiological pH

“…However, certain limitations within these sensors including the fragility of the tapered fibers that limit feasibility for real world applications. Specialty fibers like polymer optical fiber (POF) [20,21] or special technologies like SPR, femtosecond laser micromachining [22] increases the cost of the fiber sensors.…”