Randomly polarised beam produced by magnetooptically Q-switched laser.

Diode-pumped solid-state micro lasers are compact (centimetre-scale), highly stable, and efficient. Previously, we reported Q-switched lasers incorporating rare-earth substituted iron garnet (RIG) film. Here, the first demonstration of the magnetooptical (MO) Q-switch in an Nd:YAG laser cavity is performed.

Magnetic domains driving a Q-switched laser.

A 10-mm cavity length magnetooptically Q-switched Nd:GdVO 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.

Magneto-optical Q-switching using magnetic garnet film with micromagnetic domains.

High-power giant pulses can be used applied in various applications with Q-switched micro-lasers. This method can shorten the pulse duration; however, active control is currently impossible in micro-lasers. To achieve precise pulse control while maintaining compactness and simplicity, we exploit the magneto-optical effect in magnetic garnet films with micromagnetic domains that can be actively controlled by a pulsed magnetic field.

Source of low-frequency fluctuations in functional MRI signal.

Purpose: To investigate the source of native low-frequency fluctuations (LFF) in functional MRI (fMRI) signal.

Materials And Methods: Phase analysis was performed on tissue-segmented fMRI data acquired at systematically varying sampling rates.

Results: LFF in fMRI signal were both native and aliased in origin.