US 11,953,569 B2
System and method for femtotesla direct magnetic gradiometer using a multipass cell
Michael Romalis, Princeton, NJ (US); Nezih Dural, Bordentown, NJ (US); Vito-Giovanni Lucivero, Barcelona (ES); and Wonjae Lee, Princeton, NJ (US)
Assigned to THE TRUSTEES OF PRINCETON UNIVERSITY, Princeton, NJ (US)
Filed by The Trustees of Princeton University, Princeton, NJ (US)
Filed on Nov. 5, 2021, as Appl. No. 17/519,826.
Claims priority of provisional application 63/110,020, filed on Nov. 5, 2020.
Prior Publication US 2022/0137162 A1, May 5, 2022
Int. Cl. G01R 33/26 (2006.01); G02B 5/30 (2006.01); G02B 17/00 (2006.01); G02B 17/06 (2006.01); G02B 27/28 (2006.01); G02B 27/30 (2006.01)
CPC G01R 33/26 (2013.01) [G02B 17/004 (2013.01); G02B 17/0626 (2013.01); G02B 5/3083 (2013.01); G02B 27/283 (2013.01); G02B 27/30 (2013.01)] 19 Claims
OG exemplary drawing
 
1. A direct magnetic gradiometer having intrinsic subtraction of rotation signals from two atomic ensembles within a single multi-pass cell, the gradiometer comprising:
three convex spherical mirrors aligned in a V-shape geometry, the three convex spherical mirrors comprising a front mirror and two back mirrors; and
a probe laser beam configured to:
be initially focused at a near-zero angle into a hole at a center of the front mirror such that the laser beam expands at the back mirrors and nearly overlaps with itself while undergoing multiple reflections between the front and back mirrors; and
be refocused to the front mirror at different spots in a number equal to half of total beam passes before exiting.