Magnetic domains driving a Q-switched laser.

Ryohei Morimoto,Hiroyuki Takagi,Mani Mina,Hironaga Uchida,Mitsuteru Inoue,Takunori Taira,Taichi Goto,Pang Boey Lim,Yuichi Nakamura,John Pritchard

doi:10.1038/srep38679

Ryohei Morimoto, Hiroyuki Takagi + Show 8 more

Open Access

https://doi.org/10.1038/srep38679

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Abstract

A 10-mm cavity length magnetooptically Q-switched Nd:GdVO4 laser was demonstrated using a single-crystalline ferrimagnetic rare-earth iron garnet film. To design the Q-switching system, the magnetic, optical, and magnetooptical properties of the garnet film were measured. The diode pumped solid-state laser cavity was constructed using a 190-μm-thick garnet film with 58% transmittance. The garnet film had maze-shaped magnetic domains, and the domain walls disappeared when a field of over 200 Oe was applied. Therefore, the polarization state of the transmitted light was modified by modulating the magnetization, and a Q-switched pulse output with a pulse width of 5 ns and peak power of 255 W was achieved in the 10-mm-long cavity. The physical limitation of the pulse width was discussed with the calculated results.

Highlights

Rare-earth iron garnets (RIGs) are well known ferrimagnetic materials that are used in various communication applications such as optical isolators, microwave filters[1], and bubble domain memories[2]
We recently showed the first MO Q-switched laser using RIG8, but its cavity length was not any shorter than other active Q-switches even though its thickness was less than 1 mm
We report an MO Q-switch using a short cavity that cannot be realized by other active Q-switches

Summary

Introduction

Rare-earth iron garnets (RIGs) are well known ferrimagnetic materials that are used in various communication applications such as optical isolators, microwave filters[1], and bubble domain memories[2]. For a Q-switch, Q-factor modulation of a laser cavity is required to generate high-power short laser pulses. We recently showed the first MO Q-switched laser using RIG8, but its cavity length was not any shorter than other active Q-switches even though its thickness was less than 1 mm. We report an MO Q-switch using a short cavity that cannot be realized by other active Q-switches This MO Q-switch is based on the motion of magnetic micro-domains (MMDs) in a ferrimagnetic garnet film. A single-crystalline RIG film sandwiched by two coils was installed in a diode end-pumped Nd:GdVO4 laser cavity, and Q-switching operation was demonstrated using the pulsed magnetic field

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Discussion

Conclusion