Multiphoton Nanosculpting of Optical Resonant and Nonresonant Microsensors on Fiber Tips

Document Type

Article

Publication Date

4-12-2022

Abstract

This work presents a multiphoton nanosculpting process that is employed to fabricate three-dimensional (3D) mechanically assisted optical resonant and nonresonant microsensors on fiber tips. The resonant microsensor consists of a complex 3D optical cavity design with submicron resolution and advanced micromechanical features including a hinged, multipositional mirror, a 3D spring body to displace this mirror without deforming it, and adhesive-retaining features for sealing the cavity. These features represent a breakthrough in the integration and fabrication capabilities of micro-optomechanical systems. The demonstrated dynamic optical surface enables directional thin-film deposition onto obscured areas. We leverage the rotation of the dynamically movable mirror to deposit a thin reflective coating onto the inner surfaces of a Fabry–Pérot cavity (FPC) with curved geometry. The reflective coating in conjunction with the dynamically rotatable mirror greatly improves the quality factor of the FPC and enables a new class of highly integrated multipurpose sensor systems. A unique spring body FPC on an optical fiber tip is used to demonstrate pressure sensing with a sensitivity of 38 ± 7 pm/kPa over a range of −80 to 345 kPa. The nonresonant microsensor consists of microblades that spin in response to an incident flow. Light exiting the core of the optical fiber is reflected back into the fiber core at a flow-dependent rate as the blades pass by. The fiber tip flow sensor operates successfully over a range of 9–25 LPM using nitrogen gas and achieves a linear response of 706 ± 43 reflections/LPM over a range of 10.9–12 LPM. The nanostructuring technology presented in this work offers a path forward for utilizing 3D design freedom in micromechanically enhanced optical and optofluidic systems to facilitate versatile processing and advantageous geometries beyond the current state-of-the-art.

Comments

This article is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0), which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

Please fully attribute all authors of this work in any re-use, also citing the DOI: 10.1021/acsami.2c01033

The "Link to Full Text" on this page opens the article at the ACS website. A PDF is available.

DOI

10.1021/acsami.2c01033

Source Publication

ACS Applied Materials & Interfaces

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