title: High-resolution optically-detected magnetic resonance imaging in an ambient magnetic field.
abstract: Magnetic resonance imaging (MRI) in an ultralow magnetic field usually has poor spatial resolution compared to its high-field counterpart. The concomitant field effect and low signal level are among the major causes that limit the spatial resolution. Here, we report a novel imaging method, a zoom-in scheme, to achieve a reasonably high spatial resolution of 0.6 mm x 0.6mm without suffering the concomitant field effect. This method involves multiple steps of spatial encoding with gradually increased spatial resolution but reduced field-of-view. This method takes advantage of the mobility of ultralow-field MRI and the large physical size of the ambient magnetic field. We also demonstrate the use of a unique gradient solenoid to improve the efficiency of optical detection with an atomic magnetometer. The enhanced filling factor improved the signal level and consequently facilitated an improved spatial resolution.
authors.affiliation: Department of Chemistry, University of Houston, Houston, TX 77204, USA.
authors.forename: Songtham
authors.initials: S
authors.lastname: Ruangchaithaweesuk
authors.forename: Vasudeva
authors.initials: V
authors.lastname: Chintamsetti
authors.forename: Li
authors.initials: L
authors.lastname: Yao
authors.forename: Te-Wei
authors.initials: TW
authors.lastname: Tsai
authors.forename: Shoujun
authors.initials: S
authors.lastname: Xu
keywords: Atomic magnetometry; Concomitant field effect; Filling factor; Optical detection; Ultralow-field MRI; Zoom-in method