Dual-beam room-temperature atomic magnetometer with high sensitivity and large dynamic range

Abstract

We demonstrate a dual-beam high-sensitivity room temperature atomic magnetometer (AM) with large dynamic range based on nonlinear magneto-optical rotation (NMOR) enhancing scheme. Using an inelastic wave-mixing laser, we find significant NMOR signal enhancement compared with a single-beam scheme under the same far-detuned operation conditions. This dual-beam scheme is taken to operate well in the regime of lower laser intensity and off-resonance detuning. The best sensitivity achieved is 20 fT/Hz1/2 with a bandwidth of 2 kHz, substantially greater than common spin exchange relaxation free AMs. This gives a pathway to develop low-power, inexpensive miniaturized AMs for wide application.

Complete mode conversion of elastic waves by utilizing hexapole resonances in a double-scatterers structure

“…The amplitude [9,10] and phase [10,11] of elastic waves can be manipulated by the elastic metamaterials. Very recently, the elastic-wave modes [12][13][14] have been also manipulated by the elastic metamaterials, and almost complete mode conversion under normal incidence is achieved [12,[14][15][16][17][18]].…”

“…Next we compare the mode conversion based on the hexapole resonance and that based on a lower-order mode, the quadrupole resonance [18]. It is well known in metamaterials that the quadrupole resonances could induce abnormal effective shear modulus [8].…”

“…The effective shear modulus spectra for a quadrupole structure used in ref. [18] and for the hexapole structure used in this work are shown in fig. 4(a) by the black and red lines, respectively.…”

“…The conversion effect in ref. [18] (with quadrupole resonance) is still possibly attributed to its untrivial effective parameters. This work (with hexapole resonance) shows that a structure with trivial effective parameters can also induce complete mode conversion.…”

“…Unlike the monopole, dipole, and quadrupole resonance, the hexapole resonance has trivial, nearly constant effective parameters. Thus, the conversion with hexapole resonance cannot be attributed to the design of effective parameters, whose method is popular in recent related works [12,14,18,20]. Although the hexapole resonance is a relatively high-order mode, the complete conversion effect is obtained in the subwavelength region.…”