Proximal Algorithms for Discrete-Level Phase-Shifting Mask Design with Application to Optogenetics

Dimitris Ampeliotis,Christina (Tanya) Politi,Aggeliki Anastasiou,Dimitris Alexandropoulos

doi:10.3390/photonics8110477

Dimitris Ampeliotis, Christina (Tanya) Politi + Show 2 more

Open Access

https://doi.org/10.3390/photonics8110477

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Abstract

This work studies the problem of designing computer-generated holograms using phase-shifting masks limited to represent only a small number of discrete phase levels. This problem has various applications, notably in the emerging field of optogenetics and lithography. A novel regularized cost function is proposed for the problem at hand that penalizes the unfeasible phase levels. Since the proposed cost function is non-smooth, we derive proper proximal gradient algorithms for its minimization. Simulation results, considering an optogenetics application, demonstrate that the proposed proximal gradient algorithm yields better performance as compared to other algorithms proposed in the literature.

Highlights

The research area of optogenetics studies the targeted stimulation of neurons that have been previously functionalized with light-sensitive compounds, called opsins [1]
Due to the prospects that it offers for specified neuronal stimulation, the field of optogenetics has been embraced by the research community as an efficient tool towards demystifying the operation of the brain [2]
We extend our previous work in [4] that considered the problem of discrete-level phase-shifting mask design in optogenetics applications

Summary

Introduction

The research area of optogenetics studies the targeted stimulation of neurons that have been previously functionalized with light-sensitive compounds, called opsins [1]. In the sequel, structured light is used to target specific areas of the brain and stimulate the neurons to which the opsins have been attached. Due to the prospects that it offers for specified neuronal stimulation, the field of optogenetics has been embraced by the research community as an efficient tool towards demystifying the operation of the brain [2]. The optogenetic method has the potential of stimulating a complex of neurons down to a single neuron. This unprecedented specificity and spatial flexibility cannot be matched by other deep brain stimulation techniques

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