Opto-mechanical probe for combining atomic force microscopy and optical near-field surface analysis

Abstract

We have developed a new easy-to-use probe that can be used to combine atomic force microscopy (AFM) and scanning near-field optical microscopy (SNOM). We show that, using this device, the evanescent field, obtained by total internal reflection conditions in a prism, can be visualized by approaching the surface with the scanning tip. Furthermore, we were able to obtain simultaneous AFM and SNOM images of a standard test grating in air and in liquid. The lateral resolution in AFM and SNOM mode was estimated to be 45 nm and 160 nm, respectively. This new probe overcomes a number of limitations that commercial probes have, while yielding the same resolution.Scanning probe microscopy (SPM) instruments are widely recognized as valuable tools for characterizing physical, chemical, electrical, electrochemical and optical properties of materials at the nanometer scale. Atomic force microscopy (AFM), for example, is routinely used to map the surface topography with a resolution well beyond the optical limit, both in gaseous and liquid environments [1]. By replacing the standard AFM cantilever with a tipped glass fiber, one can then equip the instrument with scanning near-field optical microscopy (SNOM) capabilities. The latter can provide information on the optical field emerging from the surface of the sample with a lateral resolution of a few tens of nanometers [2,3,4]. The combination of AFM and SNOM has found applications in many fields, including cell biology and single molecule experiments [5,6].

Demonstration of atomic force microscopy imaging using an integrated opto-electro-mechanical transducer

“…Compared to other integrated devices [14][15][16][17][18], this approach has the advantages of combining the photodetection inside the mechanical sensing element and the coupling to the ridge waveguide together with its very compact footprint. Additionally, the fabrication on a III-V material may enable the integration of lasers on the same chip, leading to a fully-integrated active tip which does not require any input/output optical coupling.…”

“…Cantilever displacement sensors based on optical interference using free space and fiber optics have been also reported [12,13]. More recently, optical AFM sensors, based on interference [14,15] or evanescently-coupled resonant structures [16][17][18] with devices implemented on the cantilever itself were introduced. An increased level of optical integration was reached with nano-optomechanical displacement sensors that include the photodetector and access waveguides in the same chip [19] or even in the same device [20,21].…”

Microcantilever: Dynamical Response for Mass Sensing and Fluid Characterization

“…Regarding the second set of challenges, one may mention the expected progress in microfabrication processes and materials, which can contribute to decrease costs and make high-volume industrial applications accessible, to develop new opto-electromechanical or biological functionalities to the microcantilever, or even allow the integration of sensors in curvilinear or complex three-dimensional (3D)-shaped surfaces. New geometries have started to emerge thanks to the enhanced fabrication techniques that are available today-see, for example, hollow cantilevers [135] or probes with integrated fibre optics for sensing [136]. Additionally, interfacing the beam with a proper circuitry, and integration with complementary metal-oxide-semiconductor (CMOS), is equally a crucial step for any commercial applications that will allow us to probe higher frequencies and ever-reducing time and space scales, in real-time, contributing actively to the promised next revolution of smart cities/homes and the Internet of Things (IoT), where common spaces can be filled with sensing devices that continuously monitor the environment and communicate with one another or with people.…”

Measurement of near-field radiation intensity above a tungsten emitter using a fibrous optical microscope

“…The results agreed well with those obtained by theory with a gap of greater than several tens of nanometers. Furthermore, a rigorous measurement of near-field radiation transfer was performed using a probe of an atomic force microscope (AFM) for the case of the quartz glass plate heated by an electric current (Shen et al, 2009, Kittel, 2009, Rousseau et al, 2009, Hoorn et al, 2014. In this case, using a probe supported by a bimetal-cantilever, the radiation transfer was measured through deflection of the probe when its temperature increased, while the gap was measured as the distance from the location of contact between the probe tip and plate.…”