US 10,935,803 B2
Method to determine the topological charge of an optical beam
Enrique Jose Galvez, Hamilton, NY (US); and Behzad Khajavi, Houston, TX (US)
Assigned to COLGATE UNIVERSITY, Hamilton, NY (US)
Filed by Enrique Jose Galvez, Hamilton, NY (US); and Behzad Khajavi, Houston, TX (US)
Filed on Apr. 3, 2019, as Appl. No. 16/373,740.
Claims priority of provisional application 62/652,884, filed on Apr. 4, 2018.
Prior Publication US 2019/0310484 A1, Oct. 10, 2019
Int. Cl. G02B 27/14 (2006.01); G02B 21/36 (2006.01); G02B 23/14 (2006.01); G02B 27/09 (2006.01)
CPC G02B 27/14 (2013.01) [G02B 27/0955 (2013.01)] 7 Claims
OG exemplary drawing
 
1. An apparatus for determining a topological charge of an optical beam, comprising:
a pair of confocal lenses configured to planarize the wavefront of an optical beam extending along a first optical path;
a trapezoidal optical element aligned with the pair of confocal lenses and oriented to define a non-perpendicular angle of incidence for the optical beam so that the optical beam is reflected along a second optical patch that is different than the first optical path, wherein the trapezoidal optical element extends along an axis and has a right trapezoid cross-section along the axis such that trapezoidal optical element includes a front face formed by the right angles of the right trapezoid cross-section and an opposing rear face that is not parallel to the front face to define a non-perpendicular angle of incidence for the optical beam and wherein the reflection of the optical beam by the trapezoidal optical element produces an interference pattern that corresponds to the topological charge of the optical beam; and
an optical imager positioned along the second optical path to capture a digital image of the optical beam after reflection by the trapezoidal prism.