Microscale Temperature Shaping Using Spatial Light Modulation on Gold Nanoparticles

Ljiljana Durdevic,Serge Monneret,Hadrien M L Robert,Guillaume Baffou,Benoit Wattellier

doi:10.1038/s41598-019-40382-3

Ljiljana Durdevic, Serge Monneret + Show 3 more

Open Access

https://doi.org/10.1038/s41598-019-40382-3

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Abstract

Heating on the microscale using focused lasers gave rise to recent applications, e.g., in biomedicine, biology and microfluidics, especially using gold nanoparticles as efficient nanoabsorbers of light. However, such an approach naturally leads to nonuniform, Gaussian-like temperature distributions due to the diffusive nature of heat. Here, we report on an experimental means to generate arbitrary distributions of temperature profiles on the micrometric scale (e.g. uniform, linear, parabolic, etc) consisting in illuminating a uniform gold nanoparticle distribution on a planar substrate using spatially contrasted laser beams, shaped using a spatial light modulator (SLM). We explain how to compute the light pattern and the SLM interferogram to achieve the desired temperature distribution, and demonstrate the approach by carrying out temperature measurements using quantitative wavefront sensing.

Highlights

The task of measuring the temperature on the microscale is well-mastered by numerous optical microscopy techniques[1,21], usually based on fluorescence measurements, more rarely label-free[22,23,24,25], sometimes even in three dimensions[26], and with a diffraction-limited spatial resolution
We achieved microscale temperature shaping at will by illuminating sophisticated and non-uniform nanoparticle distributions, made by e-beam lithography, using uniform laser beams[29]. This approach suffers from a lack of flexibility: each lithographied area is associated with a predefined temperature profile that could neither be dynamically changed, nor moved to any other area of interest
We introduce an experimental procedure to dynamically generate distributions of temperature profiles on the micrometric scale with arbitrary complexity by illuminating a uniform gold nanoparticle distribution using spatially contrasted laser beams, shaped using a spatial light modulator (SLM)

Summary

Introduction

The task of measuring the temperature on the microscale is well-mastered by numerous optical microscopy techniques[1,21], usually based on fluorescence measurements, more rarely label-free[22,23,24,25], sometimes even in three dimensions[26], and with a diffraction-limited spatial resolution. Any temperature gradient can generate important thermophoretic forces on colloids dispersed in liquids[16,17,28], or non-uniform temperatures may be detrimental when working with biological systems, sensitive to temperature variations of typically 0.5 K4 For such applications, it would be important to accurately monitor the gradients or control the uniformity of the microscale temperature profile. We achieved microscale temperature shaping at will by illuminating sophisticated and non-uniform nanoparticle distributions, made by e-beam lithography, using uniform laser beams[29] Albeit effective, this approach suffers from a lack of flexibility: each lithographied area is associated with a predefined temperature profile that could neither be dynamically changed, nor moved to any other area of interest. A final part is dedicated to an illustration of the interest of this approach for the field of thermophoresis of colloids

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