Broadband Optical Detection using the Spin Seebeck Effect

TL;DR

This paper demonstrates broadband optical detection using the spin Seebeck effect in Pt/Y3Fe5O12 devices, showing flat responsivity across 390-2200 nm and introducing a field-modulation method for thermal gradient measurement.

Contribution

It introduces a novel broadband optical detection method based on spin currents and presents a field-modulation technique for precise thermal gradient measurement.

Findings

Device responsivity is flat across 390-2200 nm.

Photovoltage and heating dynamics are in strong agreement.

Broadband detection achieved with spin current-based devices.

Abstract

The generation, control, and detection of spin currents in solid-state devices are critical for Joule-heating minimization, spin-based computation, and electrical energy generation from thermal gradients. Although incorporation of spin functionality into technologically important architectures is still in its infancy, advantages over all-electric devices are increasingly becoming clear. Here, we utilize the spin Seebeck effect (SSE) in Pt/Y3Fe5O12 devices to detect light from 390 to 2200 nm. We find the device responsivity is remarkably flat across this technologically important wavelength range, closely following the Pt absorption coefficient. As expected from a SSE-generation mechanism, we observe that the photovoltage and Pt heating dynamics are in strong agreement. To precisely determine the optically created thermal gradient produced from a point-like heat source, we introduce a field-modulation method for measuring the SSE. Our results show broadband optical detection can be performed with devices based solely on spin current generation and detection.